[PATCH v2 0/2] Cleanups for the nomodeset kernel command line parameter logic

There is a lot of historical baggage on this parameter. It is defined in
the vgacon driver as nomodeset, but its set function is called text_mode()
and the value queried with a function named vgacon_text_force().

All this implies that it's about forcing text mode for VGA, yet it is not
used in neither vgacon nor other console driver. The only users for these
are DRM drivers, that check for the vgacon_text_force() return value to
determine whether the driver should be loaded or not.

That makes it quite confusing to read the code, because the variables and
function names don't reflect what they actually do and also are not in the
same subsystem as the drivers that make use of them.

This patch-set attempts to cleanup the code by moving the nomodseset param
to the DRM subsystem and do some renaming to make their intention clearer.

There is also another aspect that could be improved, and is the fact that
drivers are checking for the nomodeset being set as an indication if have
to be loaded.

But there may be other reasons why this could be the case, so it is better
to encapsulate the logic in a separate function to make clear what's about.

This is a v2 of the patches, that address the issues pointed out by Thomas
Zimmermann and Jani Nikula in v1:

https://lore.kernel.org/lkml/5b4e4534-4786-d231-e331-78fdb5d8496a@redhat.com/T/

Patch #1 adds a drm_drv_enabled() function that could be used by drivers to
check if these could be enabled, instead of just using vgacon_text_force().

Patch #2 moves the nomodeset logic to the DRM subsystem and renames the
functions and variables to better explain what these actually do.

Changes in v2:
- Squash patch to add drm_drv_enabled() and make drivers use it.
- Make the drivers changes before moving nomodeset logic to DRM.
- Make drm_drv_enabled() return an errno and -ENODEV if nomodeset.
- Remove debug and error messages in drivers.
- Conditionally build drm_nomodeset.o if CONFIG_VGA_CONSOLE is set.
- Squash patches to move nomodeset logic to DRM and do the renaming.
- Name the function drm_check_modeset() and make it return -ENODEV.

Javier Martinez Canillas (2):
  drm: Add a drm_drv_enabled() to check if drivers should be enabled
  drm: Move nomodeset kernel parameter to the DRM subsystem

 drivers/gpu/drm/Makefile                |  2 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c |  8 +++-----
 drivers/gpu/drm/ast/ast_drv.c           |  8 +++++---
 drivers/gpu/drm/drm_drv.c               | 21 ++++++++++++++++++++
 drivers/gpu/drm/drm_nomodeset.c         | 26 +++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_module.c      |  8 +++++---
 drivers/gpu/drm/mgag200/mgag200_drv.c   |  8 +++++---
 drivers/gpu/drm/nouveau/nouveau_drm.c   |  6 ++++--
 drivers/gpu/drm/qxl/qxl_drv.c           |  8 +++++---
 drivers/gpu/drm/radeon/radeon_drv.c     |  7 ++++---
 drivers/gpu/drm/tiny/bochs.c            |  8 +++++---
 drivers/gpu/drm/tiny/cirrus.c           |  9 ++++++---
 drivers/gpu/drm/vboxvideo/vbox_drv.c    | 10 +++++-----
 drivers/gpu/drm/virtio/virtgpu_drv.c    |  6 +++---
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c     |  6 +++---
 drivers/video/console/vgacon.c          | 21 --------------------
 include/drm/drm_drv.h                   |  1 +
 include/drm/drm_mode_config.h           |  6 ++++++
 include/linux/console.h                 |  6 ------
 19 files changed, 109 insertions(+), 66 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_nomodeset.c

-- 
2.33.1

The "nomodeset" kernel cmdline parameter is handled by the vgacon driver
but the exported vgacon_text_force() symbol is only used by DRM drivers.

It makes much more sense for the parameter logic to be in the subsystem
of the drivers that are making use of it.

Let's move the vgacon_text_force() function and related logic to the DRM
subsystem. While doing that, rename the function to drm_check_modeset()
which better reflects what the function is really used to test for.

Suggested-by: Daniel Vetter <redacted>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---

Changes in v2:
- Conditionally build drm_nomodeset.o if CONFIG_VGA_CONSOLE is set.
- Squash patches to move nomodeset logic to DRM and do the renaming.
- Name the function drm_check_modeset() and make it return -ENODEV.

 drivers/gpu/drm/Makefile                |  2 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c |  1 -
 drivers/gpu/drm/ast/ast_drv.c           |  1 -
 drivers/gpu/drm/drm_drv.c               |  9 +++++----
 drivers/gpu/drm/drm_nomodeset.c         | 26 +++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_module.c      |  2 --
 drivers/gpu/drm/mgag200/mgag200_drv.c   |  1 -
 drivers/gpu/drm/nouveau/nouveau_drm.c   |  1 -
 drivers/gpu/drm/qxl/qxl_drv.c           |  1 -
 drivers/gpu/drm/radeon/radeon_drv.c     |  1 -
 drivers/gpu/drm/tiny/bochs.c            |  1 -
 drivers/gpu/drm/tiny/cirrus.c           |  1 -
 drivers/gpu/drm/vboxvideo/vbox_drv.c    |  1 -
 drivers/gpu/drm/virtio/virtgpu_drv.c    |  1 -
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c     |  1 -
 drivers/video/console/vgacon.c          | 21 --------------------
 include/drm/drm_mode_config.h           |  6 ++++++
 include/linux/console.h                 |  6 ------
 18 files changed, 39 insertions(+), 44 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_nomodeset.c

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 1c41156deb5f..c74810c285af 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile

@@ -33,6 +33,8 @@ drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o drm_privacy_screen_x86.
 
 obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o
 
+obj-$(CONFIG_VGA_CONSOLE) += drm_nomodeset.o
+
 drm_cma_helper-y := drm_gem_cma_helper.o
 obj-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_cma_helper.o
 

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 7fde40d06181..b4b6993861e6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -31,7 +31,6 @@
 #include "amdgpu_drv.h"
 
 #include <drm/drm_pciids.h>
-#include <linux/console.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
 #include <linux/vga_switcheroo.h>

diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 802063279b86..6222082c3082 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c

@@ -26,7 +26,6 @@
  * Authors: Dave Airlie <airlied@redhat.com>
  */
 
-#include <linux/console.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 3fb567d62881..80b85b8ea776 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c

@@ -986,12 +986,13 @@ EXPORT_SYMBOL(drm_dev_set_unique);
  */
 int drm_drv_enabled(const struct drm_driver *driver)
 {
-	if (vgacon_text_force()) {
+	int ret;
+
+	ret = drm_check_modeset();
+	if (ret)
 		DRM_INFO("%s driver is disabled\n", driver->name);
-		return -ENODEV;
-	}
 
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL(drm_drv_enabled);
 

diff --git a/drivers/gpu/drm/drm_nomodeset.c b/drivers/gpu/drm/drm_nomodeset.c
new file mode 100644
index 000000000000..6683e396d2c5
--- /dev/null
+++ b/drivers/gpu/drm/drm_nomodeset.c

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+#include <linux/types.h>
+
+static bool drm_nomodeset;
+
+int drm_check_modeset(void)
+{
+	return drm_nomodeset ? -ENODEV : 0;
+}
+EXPORT_SYMBOL(drm_check_modeset);
+
+static int __init disable_modeset(char *str)
+{
+	drm_nomodeset = true;
+
+	pr_warn("You have booted with nomodeset. This means your GPU drivers are DISABLED\n");
+	pr_warn("Any video related functionality will be severely degraded, and you may not even be able to suspend the system properly\n");
+	pr_warn("Unless you actually understand what nomodeset does, you should reboot without enabling it\n");
+
+	return 1;
+}
+
+/* Disable kernel modesetting */
+__setup("nomodeset", disable_modeset);

diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
index 45cb3e540eff..c890c1ca20c4 100644
--- a/drivers/gpu/drm/i915/i915_module.c
+++ b/drivers/gpu/drm/i915/i915_module.c

@@ -4,8 +4,6 @@
  * Copyright © 2021 Intel Corporation
  */
 
-#include <linux/console.h>
-
 #include "gem/i915_gem_context.h"
 #include "gem/i915_gem_object.h"
 #include "i915_active.h"

diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
index 2a581094ba2b..8e000cac11ba 100644
--- a/drivers/gpu/drm/mgag200/mgag200_drv.c
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.c

@@ -6,7 +6,6 @@
  *          Dave Airlie
  */
 
-#include <linux/console.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/vmalloc.h>

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 8844d3602d87..bd1456521b7c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -22,7 +22,6 @@
  * Authors: Ben Skeggs
  */
 
-#include <linux/console.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/pci.h>

diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
index 3ac2ef2bf545..ff070ac76111 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.c
+++ b/drivers/gpu/drm/qxl/qxl_drv.c

@@ -29,7 +29,6 @@
 
 #include "qxl_drv.h"
 
-#include <linux/console.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/vgaarb.h>

diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 56d688c04346..f59cc971ec95 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c

@@ -31,7 +31,6 @@
 
 
 #include <linux/compat.h>
-#include <linux/console.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
 #include <linux/vga_switcheroo.h>

diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index ee6b1ff9128b..6e9a31f1a0f3 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c

@@ -1,6 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-#include <linux/console.h>
 #include <linux/pci.h>
 
 #include <drm/drm_aperture.h>

diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index 4706c5bc3067..659208d5aef9 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c

@@ -16,7 +16,6 @@
  * Copyright 1999-2001 Jeff Garzik <jgarzik@pobox.com>
  */
 
-#include <linux/console.h>
 #include <linux/dma-buf-map.h>
 #include <linux/module.h>
 #include <linux/pci.h>

diff --git a/drivers/gpu/drm/vboxvideo/vbox_drv.c b/drivers/gpu/drm/vboxvideo/vbox_drv.c
index e4377c37cf33..b1e63fd543bb 100644
--- a/drivers/gpu/drm/vboxvideo/vbox_drv.c
+++ b/drivers/gpu/drm/vboxvideo/vbox_drv.c

@@ -7,7 +7,6 @@
  *          Michael Thayer <michael.thayer@oracle.com,
  *          Hans de Goede <hdegoede@redhat.com>
  */
-#include <linux/console.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/vt_kern.h>

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 28200dfba2d1..ba9c0c2f8ae6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -27,7 +27,6 @@
  */
 
 #include <linux/module.h>
-#include <linux/console.h>
 #include <linux/pci.h>
 #include <linux/poll.h>
 #include <linux/wait.h>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 05e9949293d5..115ec9518277 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -25,7 +25,6 @@
  *
  **************************************************************************/
 
-#include <linux/console.h>
 #include <linux/dma-mapping.h>
 #include <linux/module.h>
 #include <linux/pci.h>

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index ef9c57ce0906..d4320b147956 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c

@@ -97,30 +97,9 @@ static int 		vga_video_font_height;
 static int 		vga_scan_lines		__read_mostly;
 static unsigned int 	vga_rolled_over; /* last vc_origin offset before wrap */
 
-static bool vgacon_text_mode_force;
 static bool vga_hardscroll_enabled;
 static bool vga_hardscroll_user_enable = true;
 
-bool vgacon_text_force(void)
-{
-	return vgacon_text_mode_force;
-}
-EXPORT_SYMBOL(vgacon_text_force);
-
-static int __init text_mode(char *str)
-{
-	vgacon_text_mode_force = true;
-
-	pr_warn("You have booted with nomodeset. This means your GPU drivers are DISABLED\n");
-	pr_warn("Any video related functionality will be severely degraded, and you may not even be able to suspend the system properly\n");
-	pr_warn("Unless you actually understand what nomodeset does, you should reboot without enabling it\n");
-
-	return 1;
-}
-
-/* force text mode - used by kernel modesetting */
-__setup("nomodeset", text_mode);
-
 static int __init no_scroll(char *str)
 {
 	/*

diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 48b7de80daf5..18982d3507e4 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h

@@ -969,4 +969,10 @@ static inline int drm_mode_config_init(struct drm_device *dev)
 void drm_mode_config_reset(struct drm_device *dev);
 void drm_mode_config_cleanup(struct drm_device *dev);
 
+#ifdef CONFIG_VGA_CONSOLE
+extern int drm_check_modeset(void);
+#else
+static inline int drm_check_modeset(void) { return 0; }
+#endif
+
 #endif

diff --git a/include/linux/console.h b/include/linux/console.h
index 20874db50bc8..d4dd8384898b 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h

@@ -217,12 +217,6 @@ extern atomic_t ignore_console_lock_warning;
 #define VESA_HSYNC_SUSPEND      2
 #define VESA_POWERDOWN          3
 
-#ifdef CONFIG_VGA_CONSOLE
-extern bool vgacon_text_force(void);
-#else
-static inline bool vgacon_text_force(void) { return false; }
-#endif
-
 extern void console_init(void);
 
 /* For deferred console takeover */

-- 
2.33.1

Hi

Am 04.11.21 um 17:07 schrieb Javier Martinez Canillas:

This now depends on the VGA textmode console. Even if you have no VGA 
console, you'd want drm_nomodeset.o. Simpledrm might be built-in and can 
provide graphics. Non-PC systems don't even have a VGA device.

I think we really want a separate boolean config option that gets 
selected by CONFIG_DRM.

I'd update this text to be less sensational.

These changes should be in patch 1?

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

On Fri, 05 Nov 2021, Thomas Zimmermann [off-list ref] wrote:

Hi

Am 04.11.21 um 17:07 schrieb Javier Martinez Canillas:

quoted

The "nomodeset" kernel cmdline parameter is handled by the vgacon driver
but the exported vgacon_text_force() symbol is only used by DRM drivers.

It makes much more sense for the parameter logic to be in the subsystem
of the drivers that are making use of it.

Let's move the vgacon_text_force() function and related logic to the DRM
subsystem. While doing that, rename the function to drm_check_modeset()
which better reflects what the function is really used to test for.

Suggested-by: Daniel Vetter <redacted>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---

Changes in v2:
- Conditionally build drm_nomodeset.o if CONFIG_VGA_CONSOLE is set.
- Squash patches to move nomodeset logic to DRM and do the renaming.
- Name the function drm_check_modeset() and make it return -ENODEV.

  drivers/gpu/drm/Makefile                |  2 ++
  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c |  1 -
  drivers/gpu/drm/ast/ast_drv.c           |  1 -
  drivers/gpu/drm/drm_drv.c               |  9 +++++----
  drivers/gpu/drm/drm_nomodeset.c         | 26 +++++++++++++++++++++++++
  drivers/gpu/drm/i915/i915_module.c      |  2 --
  drivers/gpu/drm/mgag200/mgag200_drv.c   |  1 -
  drivers/gpu/drm/nouveau/nouveau_drm.c   |  1 -
  drivers/gpu/drm/qxl/qxl_drv.c           |  1 -
  drivers/gpu/drm/radeon/radeon_drv.c     |  1 -
  drivers/gpu/drm/tiny/bochs.c            |  1 -
  drivers/gpu/drm/tiny/cirrus.c           |  1 -
  drivers/gpu/drm/vboxvideo/vbox_drv.c    |  1 -
  drivers/gpu/drm/virtio/virtgpu_drv.c    |  1 -
  drivers/gpu/drm/vmwgfx/vmwgfx_drv.c     |  1 -
  drivers/video/console/vgacon.c          | 21 --------------------
  include/drm/drm_mode_config.h           |  6 ++++++
  include/linux/console.h                 |  6 ------
  18 files changed, 39 insertions(+), 44 deletions(-)
  create mode 100644 drivers/gpu/drm/drm_nomodeset.c

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 1c41156deb5f..c74810c285af 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile

@@ -33,6 +33,8 @@ drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o drm_privacy_screen_x86.
  
  obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o
  
+obj-$(CONFIG_VGA_CONSOLE) += drm_nomodeset.o
+

This now depends on the VGA textmode console. Even if you have no VGA 
console, you'd want drm_nomodeset.o. Simpledrm might be built-in and can 
provide graphics. Non-PC systems don't even have a VGA device.

This was discussed in an earlier version, which had this builtin but the
header still had a stub for CONFIG_VGA_CONSOLE=n.

I think we really want a separate boolean config option that gets 
selected by CONFIG_DRM.

Perhaps that should be a separate change on top.

BR,
Jani.

quoted

  drm_cma_helper-y := drm_gem_cma_helper.o
  obj-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_cma_helper.o
  

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 7fde40d06181..b4b6993861e6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -31,7 +31,6 @@
  #include "amdgpu_drv.h"
  
  #include <drm/drm_pciids.h>
-#include <linux/console.h>
  #include <linux/module.h>
  #include <linux/pm_runtime.h>
  #include <linux/vga_switcheroo.h>

diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 802063279b86..6222082c3082 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c

@@ -26,7 +26,6 @@
   * Authors: Dave Airlie <airlied@redhat.com>
   */
  
-#include <linux/console.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 3fb567d62881..80b85b8ea776 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c

@@ -986,12 +986,13 @@ EXPORT_SYMBOL(drm_dev_set_unique);
   */
  int drm_drv_enabled(const struct drm_driver *driver)
  {
-	if (vgacon_text_force()) {
+	int ret;
+
+	ret = drm_check_modeset();
+	if (ret)
  		DRM_INFO("%s driver is disabled\n", driver->name);
-		return -ENODEV;
-	}
  
-	return 0;
+	return ret;
  }
  EXPORT_SYMBOL(drm_drv_enabled);
  

diff --git a/drivers/gpu/drm/drm_nomodeset.c b/drivers/gpu/drm/drm_nomodeset.c
new file mode 100644
index 000000000000..6683e396d2c5
--- /dev/null
+++ b/drivers/gpu/drm/drm_nomodeset.c

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+#include <linux/types.h>
+
+static bool drm_nomodeset;
+
+int drm_check_modeset(void)
+{
+	return drm_nomodeset ? -ENODEV : 0;
+}
+EXPORT_SYMBOL(drm_check_modeset);
+
+static int __init disable_modeset(char *str)
+{
+	drm_nomodeset = true;
+
+	pr_warn("You have booted with nomodeset. This means your GPU drivers are DISABLED\n");
+	pr_warn("Any video related functionality will be severely degraded, and you may not even be able to suspend the system properly\n");
+	pr_warn("Unless you actually understand what nomodeset does, you should reboot without enabling it\n");

I'd update this text to be less sensational.

quoted

+
+	return 1;
+}
+
+/* Disable kernel modesetting */
+__setup("nomodeset", disable_modeset);

diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
index 45cb3e540eff..c890c1ca20c4 100644
--- a/drivers/gpu/drm/i915/i915_module.c
+++ b/drivers/gpu/drm/i915/i915_module.c

@@ -4,8 +4,6 @@
   * Copyright © 2021 Intel Corporation
   */
  
-#include <linux/console.h>
-

These changes should be in patch 1?

quoted

  #include "gem/i915_gem_context.h"
  #include "gem/i915_gem_object.h"
  #include "i915_active.h"

diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
index 2a581094ba2b..8e000cac11ba 100644
--- a/drivers/gpu/drm/mgag200/mgag200_drv.c
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.c

@@ -6,7 +6,6 @@
   *          Dave Airlie
   */
  
-#include <linux/console.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  #include <linux/vmalloc.h>

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 8844d3602d87..bd1456521b7c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -22,7 +22,6 @@
   * Authors: Ben Skeggs
   */
  
-#include <linux/console.h>
  #include <linux/delay.h>
  #include <linux/module.h>
  #include <linux/pci.h>

diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
index 3ac2ef2bf545..ff070ac76111 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.c
+++ b/drivers/gpu/drm/qxl/qxl_drv.c

@@ -29,7 +29,6 @@
  
  #include "qxl_drv.h"
  
-#include <linux/console.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  #include <linux/vgaarb.h>

diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 56d688c04346..f59cc971ec95 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c

@@ -31,7 +31,6 @@
  
  
  #include <linux/compat.h>
-#include <linux/console.h>
  #include <linux/module.h>
  #include <linux/pm_runtime.h>
  #include <linux/vga_switcheroo.h>

diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index ee6b1ff9128b..6e9a31f1a0f3 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c

@@ -1,6 +1,5 @@
  // SPDX-License-Identifier: GPL-2.0-or-later
  
-#include <linux/console.h>
  #include <linux/pci.h>
  
  #include <drm/drm_aperture.h>

diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index 4706c5bc3067..659208d5aef9 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c

@@ -16,7 +16,6 @@
   * Copyright 1999-2001 Jeff Garzik <jgarzik@pobox.com>
   */
  
-#include <linux/console.h>
  #include <linux/dma-buf-map.h>
  #include <linux/module.h>
  #include <linux/pci.h>

diff --git a/drivers/gpu/drm/vboxvideo/vbox_drv.c b/drivers/gpu/drm/vboxvideo/vbox_drv.c
index e4377c37cf33..b1e63fd543bb 100644
--- a/drivers/gpu/drm/vboxvideo/vbox_drv.c
+++ b/drivers/gpu/drm/vboxvideo/vbox_drv.c

@@ -7,7 +7,6 @@
   *          Michael Thayer <michael.thayer@oracle.com,
   *          Hans de Goede <hdegoede@redhat.com>
   */
-#include <linux/console.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  #include <linux/vt_kern.h>

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 28200dfba2d1..ba9c0c2f8ae6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -27,7 +27,6 @@
   */
  
  #include <linux/module.h>
-#include <linux/console.h>
  #include <linux/pci.h>
  #include <linux/poll.h>
  #include <linux/wait.h>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 05e9949293d5..115ec9518277 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -25,7 +25,6 @@
   *
   **************************************************************************/
  
-#include <linux/console.h>
  #include <linux/dma-mapping.h>
  #include <linux/module.h>
  #include <linux/pci.h>

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index ef9c57ce0906..d4320b147956 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c

@@ -97,30 +97,9 @@ static int 		vga_video_font_height;
  static int 		vga_scan_lines		__read_mostly;
  static unsigned int 	vga_rolled_over; /* last vc_origin offset before wrap */
  
-static bool vgacon_text_mode_force;
  static bool vga_hardscroll_enabled;
  static bool vga_hardscroll_user_enable = true;
  
-bool vgacon_text_force(void)
-{
-	return vgacon_text_mode_force;
-}
-EXPORT_SYMBOL(vgacon_text_force);
-
-static int __init text_mode(char *str)
-{
-	vgacon_text_mode_force = true;
-
-	pr_warn("You have booted with nomodeset. This means your GPU drivers are DISABLED\n");
-	pr_warn("Any video related functionality will be severely degraded, and you may not even be able to suspend the system properly\n");
-	pr_warn("Unless you actually understand what nomodeset does, you should reboot without enabling it\n");
-
-	return 1;
-}
-
-/* force text mode - used by kernel modesetting */
-__setup("nomodeset", text_mode);
-
  static int __init no_scroll(char *str)
  {
  	/*

diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 48b7de80daf5..18982d3507e4 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h

@@ -969,4 +969,10 @@ static inline int drm_mode_config_init(struct drm_device *dev)
  void drm_mode_config_reset(struct drm_device *dev);
  void drm_mode_config_cleanup(struct drm_device *dev);
  
+#ifdef CONFIG_VGA_CONSOLE
+extern int drm_check_modeset(void);
+#else
+static inline int drm_check_modeset(void) { return 0; }
+#endif
+
  #endif

diff --git a/include/linux/console.h b/include/linux/console.h
index 20874db50bc8..d4dd8384898b 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h

@@ -217,12 +217,6 @@ extern atomic_t ignore_console_lock_warning;
  #define VESA_HSYNC_SUSPEND      2
  #define VESA_POWERDOWN          3
  
-#ifdef CONFIG_VGA_CONSOLE
-extern bool vgacon_text_force(void);
-#else
-static inline bool vgacon_text_force(void) { return false; }
-#endif
-
  extern void console_init(void);
  
  /* For deferred console takeover */

-- 
Jani Nikula, Intel Open Source Graphics Center

Hi

Am 05.11.21 um 10:22 schrieb Jani Nikula:

On Fri, 05 Nov 2021, Thomas Zimmermann [off-list ref] wrote:

quoted

Hi

Am 04.11.21 um 17:07 schrieb Javier Martinez Canillas:

quoted

The "nomodeset" kernel cmdline parameter is handled by the vgacon driver
but the exported vgacon_text_force() symbol is only used by DRM drivers.

It makes much more sense for the parameter logic to be in the subsystem
of the drivers that are making use of it.

Let's move the vgacon_text_force() function and related logic to the DRM
subsystem. While doing that, rename the function to drm_check_modeset()
which better reflects what the function is really used to test for.

Suggested-by: Daniel Vetter <redacted>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---

Changes in v2:
- Conditionally build drm_nomodeset.o if CONFIG_VGA_CONSOLE is set.
- Squash patches to move nomodeset logic to DRM and do the renaming.
- Name the function drm_check_modeset() and make it return -ENODEV.

   drivers/gpu/drm/Makefile                |  2 ++
   drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c |  1 -
   drivers/gpu/drm/ast/ast_drv.c           |  1 -
   drivers/gpu/drm/drm_drv.c               |  9 +++++----
   drivers/gpu/drm/drm_nomodeset.c         | 26 +++++++++++++++++++++++++
   drivers/gpu/drm/i915/i915_module.c      |  2 --
   drivers/gpu/drm/mgag200/mgag200_drv.c   |  1 -
   drivers/gpu/drm/nouveau/nouveau_drm.c   |  1 -
   drivers/gpu/drm/qxl/qxl_drv.c           |  1 -
   drivers/gpu/drm/radeon/radeon_drv.c     |  1 -
   drivers/gpu/drm/tiny/bochs.c            |  1 -
   drivers/gpu/drm/tiny/cirrus.c           |  1 -
   drivers/gpu/drm/vboxvideo/vbox_drv.c    |  1 -
   drivers/gpu/drm/virtio/virtgpu_drv.c    |  1 -
   drivers/gpu/drm/vmwgfx/vmwgfx_drv.c     |  1 -
   drivers/video/console/vgacon.c          | 21 --------------------
   include/drm/drm_mode_config.h           |  6 ++++++
   include/linux/console.h                 |  6 ------
   18 files changed, 39 insertions(+), 44 deletions(-)
   create mode 100644 drivers/gpu/drm/drm_nomodeset.c

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 1c41156deb5f..c74810c285af 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile

@@ -33,6 +33,8 @@ drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o drm_privacy_screen_x86.
   
   obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o
   
+obj-$(CONFIG_VGA_CONSOLE) += drm_nomodeset.o
+

This now depends on the VGA textmode console. Even if you have no VGA
console, you'd want drm_nomodeset.o. Simpledrm might be built-in and can
provide graphics. Non-PC systems don't even have a VGA device.

This was discussed in an earlier version, which had this builtin but the
header still had a stub for CONFIG_VGA_CONSOLE=n.

quoted

I think we really want a separate boolean config option that gets
selected by CONFIG_DRM.

Perhaps that should be a separate change on top.

Sure, make it a separate patch.

We want to make this work on ARM systems. I even have a request to 
replace offb on Power architecture by simpledrm. So the final config has 
to be system agnostic.

Best regards
Thomas

BR,
Jani.

quoted

quoted

   drm_cma_helper-y := drm_gem_cma_helper.o
   obj-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_cma_helper.o
   

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 7fde40d06181..b4b6993861e6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -31,7 +31,6 @@
   #include "amdgpu_drv.h"
   
   #include <drm/drm_pciids.h>
-#include <linux/console.h>
   #include <linux/module.h>
   #include <linux/pm_runtime.h>
   #include <linux/vga_switcheroo.h>

diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 802063279b86..6222082c3082 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c

@@ -26,7 +26,6 @@
    * Authors: Dave Airlie <airlied@redhat.com>
    */
   
-#include <linux/console.h>
   #include <linux/module.h>
   #include <linux/pci.h>
   

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 3fb567d62881..80b85b8ea776 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c

@@ -986,12 +986,13 @@ EXPORT_SYMBOL(drm_dev_set_unique);
    */
   int drm_drv_enabled(const struct drm_driver *driver)
   {
-	if (vgacon_text_force()) {
+	int ret;
+
+	ret = drm_check_modeset();
+	if (ret)
   		DRM_INFO("%s driver is disabled\n", driver->name);
-		return -ENODEV;
-	}
   
-	return 0;
+	return ret;
   }
   EXPORT_SYMBOL(drm_drv_enabled);
   

diff --git a/drivers/gpu/drm/drm_nomodeset.c b/drivers/gpu/drm/drm_nomodeset.c
new file mode 100644
index 000000000000..6683e396d2c5
--- /dev/null
+++ b/drivers/gpu/drm/drm_nomodeset.c

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+#include <linux/types.h>
+
+static bool drm_nomodeset;
+
+int drm_check_modeset(void)
+{
+	return drm_nomodeset ? -ENODEV : 0;
+}
+EXPORT_SYMBOL(drm_check_modeset);
+
+static int __init disable_modeset(char *str)
+{
+	drm_nomodeset = true;
+
+	pr_warn("You have booted with nomodeset. This means your GPU drivers are DISABLED\n");
+	pr_warn("Any video related functionality will be severely degraded, and you may not even be able to suspend the system properly\n");
+	pr_warn("Unless you actually understand what nomodeset does, you should reboot without enabling it\n");

I'd update this text to be less sensational.

quoted

+
+	return 1;
+}
+
+/* Disable kernel modesetting */
+__setup("nomodeset", disable_modeset);

diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
index 45cb3e540eff..c890c1ca20c4 100644
--- a/drivers/gpu/drm/i915/i915_module.c
+++ b/drivers/gpu/drm/i915/i915_module.c

@@ -4,8 +4,6 @@
    * Copyright © 2021 Intel Corporation
    */
   
-#include <linux/console.h>
-

These changes should be in patch 1?

quoted

   #include "gem/i915_gem_context.h"
   #include "gem/i915_gem_object.h"
   #include "i915_active.h"

diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
index 2a581094ba2b..8e000cac11ba 100644
--- a/drivers/gpu/drm/mgag200/mgag200_drv.c
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.c

@@ -6,7 +6,6 @@
    *          Dave Airlie
    */
   
-#include <linux/console.h>
   #include <linux/module.h>
   #include <linux/pci.h>
   #include <linux/vmalloc.h>

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 8844d3602d87..bd1456521b7c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -22,7 +22,6 @@
    * Authors: Ben Skeggs
    */
   
-#include <linux/console.h>
   #include <linux/delay.h>
   #include <linux/module.h>
   #include <linux/pci.h>

diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
index 3ac2ef2bf545..ff070ac76111 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.c
+++ b/drivers/gpu/drm/qxl/qxl_drv.c

@@ -29,7 +29,6 @@
   
   #include "qxl_drv.h"
   
-#include <linux/console.h>
   #include <linux/module.h>
   #include <linux/pci.h>
   #include <linux/vgaarb.h>

diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 56d688c04346..f59cc971ec95 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c

@@ -31,7 +31,6 @@
   
   
   #include <linux/compat.h>
-#include <linux/console.h>
   #include <linux/module.h>
   #include <linux/pm_runtime.h>
   #include <linux/vga_switcheroo.h>

diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index ee6b1ff9128b..6e9a31f1a0f3 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c

@@ -1,6 +1,5 @@
   // SPDX-License-Identifier: GPL-2.0-or-later
   
-#include <linux/console.h>
   #include <linux/pci.h>
   
   #include <drm/drm_aperture.h>

diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index 4706c5bc3067..659208d5aef9 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c

@@ -16,7 +16,6 @@
    * Copyright 1999-2001 Jeff Garzik <jgarzik@pobox.com>
    */
   
-#include <linux/console.h>
   #include <linux/dma-buf-map.h>
   #include <linux/module.h>
   #include <linux/pci.h>

diff --git a/drivers/gpu/drm/vboxvideo/vbox_drv.c b/drivers/gpu/drm/vboxvideo/vbox_drv.c
index e4377c37cf33..b1e63fd543bb 100644
--- a/drivers/gpu/drm/vboxvideo/vbox_drv.c
+++ b/drivers/gpu/drm/vboxvideo/vbox_drv.c

@@ -7,7 +7,6 @@
    *          Michael Thayer <michael.thayer@oracle.com,
    *          Hans de Goede <hdegoede@redhat.com>
    */
-#include <linux/console.h>
   #include <linux/module.h>
   #include <linux/pci.h>
   #include <linux/vt_kern.h>

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 28200dfba2d1..ba9c0c2f8ae6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -27,7 +27,6 @@
    */
   
   #include <linux/module.h>
-#include <linux/console.h>
   #include <linux/pci.h>
   #include <linux/poll.h>
   #include <linux/wait.h>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 05e9949293d5..115ec9518277 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -25,7 +25,6 @@
    *
    **************************************************************************/
   
-#include <linux/console.h>
   #include <linux/dma-mapping.h>
   #include <linux/module.h>
   #include <linux/pci.h>

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index ef9c57ce0906..d4320b147956 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c

@@ -97,30 +97,9 @@ static int 		vga_video_font_height;
   static int 		vga_scan_lines		__read_mostly;
   static unsigned int 	vga_rolled_over; /* last vc_origin offset before wrap */
   
-static bool vgacon_text_mode_force;
   static bool vga_hardscroll_enabled;
   static bool vga_hardscroll_user_enable = true;
   
-bool vgacon_text_force(void)
-{
-	return vgacon_text_mode_force;
-}
-EXPORT_SYMBOL(vgacon_text_force);
-
-static int __init text_mode(char *str)
-{
-	vgacon_text_mode_force = true;
-
-	pr_warn("You have booted with nomodeset. This means your GPU drivers are DISABLED\n");
-	pr_warn("Any video related functionality will be severely degraded, and you may not even be able to suspend the system properly\n");
-	pr_warn("Unless you actually understand what nomodeset does, you should reboot without enabling it\n");
-
-	return 1;
-}
-
-/* force text mode - used by kernel modesetting */
-__setup("nomodeset", text_mode);
-
   static int __init no_scroll(char *str)
   {
   	/*

diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 48b7de80daf5..18982d3507e4 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h

@@ -969,4 +969,10 @@ static inline int drm_mode_config_init(struct drm_device *dev)
   void drm_mode_config_reset(struct drm_device *dev);
   void drm_mode_config_cleanup(struct drm_device *dev);
   
+#ifdef CONFIG_VGA_CONSOLE
+extern int drm_check_modeset(void);
+#else
+static inline int drm_check_modeset(void) { return 0; }
+#endif
+
   #endif

diff --git a/include/linux/console.h b/include/linux/console.h
index 20874db50bc8..d4dd8384898b 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h

@@ -217,12 +217,6 @@ extern atomic_t ignore_console_lock_warning;
   #define VESA_HSYNC_SUSPEND      2
   #define VESA_POWERDOWN          3
   
-#ifdef CONFIG_VGA_CONSOLE
-extern bool vgacon_text_force(void);
-#else
-static inline bool vgacon_text_force(void) { return false; }
-#endif
-
   extern void console_init(void);
   
   /* For deferred console takeover */

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

On 11/5/21 10:00, Thomas Zimmermann wrote:

[snip]

quoted

+
+static int __init disable_modeset(char *str)
+{
+	drm_nomodeset = true;
+
+	pr_warn("You have booted with nomodeset. This means your GPU drivers are DISABLED\n");
+	pr_warn("Any video related functionality will be severely degraded, and you may not even be able to suspend the system properly\n");
+	pr_warn("Unless you actually understand what nomodeset does, you should reboot without enabling it\n");

I'd update this text to be less sensational.

This is indeed quite sensational. But think we can do it as a follow-up patch.

Since we will have to stick with nomodeset for backward compatibility, I was
planning to add documentation to explain what this parameter is about and what
is the actual effect of setting it.

So I think we can change this as a part of that patch-set.
 

quoted

+
+	return 1;
+}
+
+/* Disable kernel modesetting */
+__setup("nomodeset", disable_modeset);

diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
index 45cb3e540eff..c890c1ca20c4 100644
--- a/drivers/gpu/drm/i915/i915_module.c
+++ b/drivers/gpu/drm/i915/i915_module.c

@@ -4,8 +4,6 @@
   * Copyright © 2021 Intel Corporation
   */
  
-#include <linux/console.h>
-

These changes should be in patch 1?

Yes, I forgot to move these when changed the order of the patches.

Best regards, -- 
Javier Martinez Canillas
Linux Engineering
Red Hat

On 11/5/21 10:39, Thomas Zimmermann wrote:

[snip]

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+obj-$(CONFIG_VGA_CONSOLE) += drm_nomodeset.o
+

This now depends on the VGA textmode console. Even if you have no VGA
console, you'd want drm_nomodeset.o. Simpledrm might be built-in and can
provide graphics. Non-PC systems don't even have a VGA device.

This was discussed in an earlier version, which had this builtin but the
header still had a stub for CONFIG_VGA_CONSOLE=n.

quoted

I think we really want a separate boolean config option that gets
selected by CONFIG_DRM.

Perhaps that should be a separate change on top.

Sure, make it a separate patch.

Agreed. I was planning to do it as a follow-up as well and drop the
#ifdef CONFIG_VGA_CONSOLE guard in the header.
 

We want to make this work on ARM systems. I even have a request to 
replace offb on Power architecture by simpledrm. So the final config has 
to be system agnostic.

Same, since we want to drop the fbdev drivers in Fedora, for all arches.
 

Best regards
Thomas

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat