@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPERhelpFBDEVhelpersforKMSdrivers.+configDRM_FBDEV_EMULATION+bool"Enable legacy fbdev support for your modesetting driver"+depends onDRM+selectDRM_KMS_HELPER+selectDRM_KMS_FB_HELPER+selectFB_SYS_FILLRECT+selectFB_SYS_COPYAREA+selectFB_SYS_IMAGEBLIT+selectFB_SYS_FOPS+selectFB_CFB_FILLRECT+selectFB_CFB_COPYAREA+selectFB_CFB_IMAGEBLIT+defaulty+help+Choosethisoptionifyouhaveaneedforthelegacyfbdev+support.Notethatthissupportalsoprovidethelinuxconsole+supportontopofyourmodesettingdriver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why doesn't
it?
There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
quoted
quoted
quoted
Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
replace them with 'select DRM_FBDEV_EMULATION'?
Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
for fb related function calls/declarations in each driver, something that's
already done for i915 and msm drivers.
The problem with the patch as-is the massive amounts of selects the FB
helper still has. We need to get rid of them so that when you disable
fbdev emulation you can indeed disable fbcon and the entire fbdev
subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
doesn't work we need to look again how to better stub things out I think.
That's true. Also, as Jani pointed out, maybe it isn't the best idea to make
every kms driver select DRM_FBDEV_EMULATION?
Maybe the drivers that are currently built with fbdev emulation by default
can add a 'depends on DRM_FBDEV_EMULATION'? Since the config defaults to y,
the drivers should run as is. Later, we could take up each driver and build
the fb stuff only when DRM_FBDEV_EMULATION is set, like how we do for i915
and msm?
Yeah we definitely can't mix select with a user-visible option. I think we
just need to fix up the remaining functions and create stubs for them if
needed and then drop all the selects. Well in DRM_FBDEV_EMULATION we
should still select for fbcon since otherwise tons of bug reports about
"where is my fbcon with kms?".
I'll give this a try. Although, it would be a better idea to make the
drivers not call these at all when fbdev emulation isn't asked for. With
the stubs, if someone does try to use the driver with
DRM_FBDEV_EMULATION not set, the worst that'll happen would be that the
driver fails to probe. Which isn't so bad.
Archit
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPERhelpFBDEVhelpersforKMSdrivers.+configDRM_FBDEV_EMULATION+bool"Enable legacy fbdev support for your modesetting driver"+depends onDRM+selectDRM_KMS_HELPER+selectDRM_KMS_FB_HELPER+selectFB_SYS_FILLRECT+selectFB_SYS_COPYAREA+selectFB_SYS_IMAGEBLIT+selectFB_SYS_FOPS+selectFB_CFB_FILLRECT+selectFB_CFB_COPYAREA+selectFB_CFB_IMAGEBLIT+defaulty+help+Choosethisoptionifyouhaveaneedforthelegacyfbdev+support.Notethatthissupportalsoprovidethelinuxconsole+supportontopofyourmodesettingdriver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why doesn't
it?
There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h
2. Then we add stubs for these functions in drm_fb_helper.h, like this
#if defined(CONFIG_FB)
#include <linux/fb.h>
#else
/* static inline stubs for all the fb stuff used by kms drivers */
#endif
Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.
What do you think?
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPERhelpFBDEVhelpersforKMSdrivers.+configDRM_FBDEV_EMULATION+bool"Enable legacy fbdev support for your modesetting driver"+depends onDRM+selectDRM_KMS_HELPER+selectDRM_KMS_FB_HELPER+selectFB_SYS_FILLRECT+selectFB_SYS_COPYAREA+selectFB_SYS_IMAGEBLIT+selectFB_SYS_FOPS+selectFB_CFB_FILLRECT+selectFB_CFB_COPYAREA+selectFB_CFB_IMAGEBLIT+defaulty+help+Choosethisoptionifyouhaveaneedforthelegacyfbdev+support.Notethatthissupportalsoprovidethelinuxconsole+supportontopofyourmodesettingdriver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why doesn't
it?
There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h
2. Then we add stubs for these functions in drm_fb_helper.h, like this
#if defined(CONFIG_FB)
#include <linux/fb.h>
#else
/* static inline stubs for all the fb stuff used by kms drivers */
#endif
Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.
What do you think?
This looks good! I'll give it a try.
Archit
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPERhelpFBDEVhelpersforKMSdrivers.+configDRM_FBDEV_EMULATION+bool"Enable legacy fbdev support for your modesetting driver"+depends onDRM+selectDRM_KMS_HELPER+selectDRM_KMS_FB_HELPER+selectFB_SYS_FILLRECT+selectFB_SYS_COPYAREA+selectFB_SYS_IMAGEBLIT+selectFB_SYS_FOPS+selectFB_CFB_FILLRECT+selectFB_CFB_COPYAREA+selectFB_CFB_IMAGEBLIT+defaulty+help+Choosethisoptionifyouhaveaneedforthelegacyfbdev+support.Notethatthissupportalsoprovidethelinuxconsole+supportontopofyourmodesettingdriver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why doesn't
it?
There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h
2. Then we add stubs for these functions in drm_fb_helper.h, like this
#if defined(CONFIG_FB)
#include <linux/fb.h>
#else
/* static inline stubs for all the fb stuff used by kms drivers */
#endif
Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.
I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.
I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h
itself, but that seemed a bit too intrusive.
This is what I'm currently doing:
- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap
would actually benefit if we have drm fb helpers for them. They are used
in exactly the same manner by all the drivers.
- For the rest of the functions that are sparsely used, I was
considering making very simple drm_fb_* wrapper functions. Something like:
void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
if (helper->fbdev)
fb_deferred_io_init(helper->fbdev);
}
We could have all fb calls called within drm_fb_helper.c, creating
drm_fb_helper_* stub functions would then be an easier task. What do you
think?
Archit
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPERhelpFBDEVhelpersforKMSdrivers.+configDRM_FBDEV_EMULATION+bool"Enable legacy fbdev support for your modesetting driver"+depends onDRM+selectDRM_KMS_HELPER+selectDRM_KMS_FB_HELPER+selectFB_SYS_FILLRECT+selectFB_SYS_COPYAREA+selectFB_SYS_IMAGEBLIT+selectFB_SYS_FOPS+selectFB_CFB_FILLRECT+selectFB_CFB_COPYAREA+selectFB_CFB_IMAGEBLIT+defaulty+help+Choosethisoptionifyouhaveaneedforthelegacyfbdev+support.Notethatthissupportalsoprovidethelinuxconsole+supportontopofyourmodesettingdriver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why doesn't
it?
There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h
2. Then we add stubs for these functions in drm_fb_helper.h, like this
#if defined(CONFIG_FB)
#include <linux/fb.h>
#else
/* static inline stubs for all the fb stuff used by kms drivers */
#endif
Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.
I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.
I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
but that seemed a bit too intrusive.
This is what I'm currently doing:
- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.
- For the rest of the functions that are sparsely used, I was considering
making very simple drm_fb_* wrapper functions. Something like:
void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
if (helper->fbdev)
fb_deferred_io_init(helper->fbdev);
}
We could have all fb calls called within drm_fb_helper.c, creating
drm_fb_helper_* stub functions would then be an easier task. What do you
think?
That's actually an option I considered, but I hoped we could do it with
less work. If this indeed works and you can create the patch that would be
awesome.
Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
From: Daniel Vetter <hidden> Date: 2015-06-30 07:10:30
Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.
-Daniel
On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter [off-list ref] wrote:
On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:
quoted
Hi,
On 03/13/2015 02:36 PM, Daniel Vetter wrote:
quoted
On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
quoted
On 03/11/2015 08:47 PM, Daniel Vetter wrote:
quoted
On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 05:47 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 03:35 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 03:17 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPERhelpFBDEVhelpersforKMSdrivers.+configDRM_FBDEV_EMULATION+bool"Enable legacy fbdev support for your modesetting driver"+depends onDRM+selectDRM_KMS_HELPER+selectDRM_KMS_FB_HELPER+selectFB_SYS_FILLRECT+selectFB_SYS_COPYAREA+selectFB_SYS_IMAGEBLIT+selectFB_SYS_FOPS+selectFB_CFB_FILLRECT+selectFB_CFB_COPYAREA+selectFB_CFB_IMAGEBLIT+defaulty+help+Choosethisoptionifyouhaveaneedforthelegacyfbdev+support.Notethatthissupportalsoprovidethelinuxconsole+supportontopofyourmodesettingdriver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why doesn't
it?
There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h
2. Then we add stubs for these functions in drm_fb_helper.h, like this
#if defined(CONFIG_FB)
#include <linux/fb.h>
#else
/* static inline stubs for all the fb stuff used by kms drivers */
#endif
Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.
I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.
I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
but that seemed a bit too intrusive.
This is what I'm currently doing:
- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.
- For the rest of the functions that are sparsely used, I was considering
making very simple drm_fb_* wrapper functions. Something like:
void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
if (helper->fbdev)
fb_deferred_io_init(helper->fbdev);
}
We could have all fb calls called within drm_fb_helper.c, creating
drm_fb_helper_* stub functions would then be an easier task. What do you
think?
That's actually an option I considered, but I hoped we could do it with
less work. If this indeed works and you can create the patch that would be
awesome.
Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.
I'd started on this again. I've got more free time now than before, so I
should have something in a week or so. I agree it will help a lot (there
are already two new drivers since we started discussing this!)
Archit
-Daniel
On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter [off-list ref] wrote:
quoted
On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:
quoted
Hi,
On 03/13/2015 02:36 PM, Daniel Vetter wrote:
quoted
On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
quoted
On 03/11/2015 08:47 PM, Daniel Vetter wrote:
quoted
On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 05:47 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 03:35 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 03:17 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPERhelpFBDEVhelpersforKMSdrivers.+configDRM_FBDEV_EMULATION+bool"Enable legacy fbdev support for your modesetting driver"+depends onDRM+selectDRM_KMS_HELPER+selectDRM_KMS_FB_HELPER+selectFB_SYS_FILLRECT+selectFB_SYS_COPYAREA+selectFB_SYS_IMAGEBLIT+selectFB_SYS_FOPS+selectFB_CFB_FILLRECT+selectFB_CFB_COPYAREA+selectFB_CFB_IMAGEBLIT+defaulty+help+Choosethisoptionifyouhaveaneedforthelegacyfbdev+support.Notethatthissupportalsoprovidethelinuxconsole+supportontopofyourmodesettingdriver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why doesn't
it?
There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h
2. Then we add stubs for these functions in drm_fb_helper.h, like this
#if defined(CONFIG_FB)
#include <linux/fb.h>
#else
/* static inline stubs for all the fb stuff used by kms drivers */
#endif
Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.
I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.
I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
but that seemed a bit too intrusive.
This is what I'm currently doing:
- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.
- For the rest of the functions that are sparsely used, I was considering
making very simple drm_fb_* wrapper functions. Something like:
void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
if (helper->fbdev)
fb_deferred_io_init(helper->fbdev);
}
We could have all fb calls called within drm_fb_helper.c, creating
drm_fb_helper_* stub functions would then be an easier task. What do you
think?
That's actually an option I considered, but I hoped we could do it with
less work. If this indeed works and you can create the patch that would be
awesome.
Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.
I'd started on this again. I've got more free time now than before, so I
should have something in a week or so. I agree it will help a lot (there are
already two new drivers since we started discussing this!)
Archit
quoted
-Daniel
On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter [off-list ref] wrote:
quoted
On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:
quoted
Hi,
On 03/13/2015 02:36 PM, Daniel Vetter wrote:
quoted
On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
quoted
On 03/11/2015 08:47 PM, Daniel Vetter wrote:
quoted
On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 05:47 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 03:35 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 03:17 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
driver"
+ depends on DRM
+ select DRM_KMS_HELPER
+ select DRM_KMS_FB_HELPER
+ select FB_SYS_FILLRECT
+ select FB_SYS_COPYAREA
+ select FB_SYS_IMAGEBLIT
+ select FB_SYS_FOPS
+ select FB_CFB_FILLRECT
+ select FB_CFB_COPYAREA
+ select FB_CFB_IMAGEBLIT
+ default y
+ help
+ Choose this option if you have a need for the legacy
fbdev
+ support. Note that this support also provide the linux
console
+ support on top of your modesetting driver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more
patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all
drm
drivers. Otherwise this knob here won't work by default if you
e.g. select
radeon. In general we can't mix explicit options with menu
entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff
internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why
doesn't
it?
There are still calls to functions from fb core like fb_set_suspend
and
register_framebuffer which aren't covered by the drm fb helper
functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm
drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into
drm_fb_helper.h
2. Then we add stubs for these functions in drm_fb_helper.h, like this
#if defined(CONFIG_FB)
#include <linux/fb.h>
#else
/* static inline stubs for all the fb stuff used by kms drivers */
#endif
Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.
I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.
I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h
itself,
but that seemed a bit too intrusive.
This is what I'm currently doing:
- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap
would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.
- For the rest of the functions that are sparsely used, I was
considering
making very simple drm_fb_* wrapper functions. Something like:
void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
if (helper->fbdev)
fb_deferred_io_init(helper->fbdev);
}
We could have all fb calls called within drm_fb_helper.c, creating
drm_fb_helper_* stub functions would then be an easier task. What do you
think?
That's actually an option I considered, but I hoped we could do it with
less work. If this indeed works and you can create the patch that would
be
awesome.
Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
--
Benjamin Gaignard
Graphic Working Group
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
Hm, the point of the kconfig is to not require all the legacy baggage
from fbdev. But I guess a module option could be added later on too.
bochs has it too.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
I guess this won't be hard to do once we have a common fbdev emulation
config option. We could consider this as a drm top level module param.
I'll keep this in mind.
Thanks,
Archit
Benjamin
2015-06-30 9:56 GMT+02:00 Archit Taneja [off-list ref]:
quoted
Hi,
On 06/30/2015 12:40 PM, Daniel Vetter wrote:
quoted
Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.
I'd started on this again. I've got more free time now than before, so I
should have something in a week or so. I agree it will help a lot (there are
already two new drivers since we started discussing this!)
Archit
quoted
-Daniel
On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter [off-list ref] wrote:
quoted
On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:
quoted
Hi,
On 03/13/2015 02:36 PM, Daniel Vetter wrote:
quoted
On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
quoted
On 03/11/2015 08:47 PM, Daniel Vetter wrote:
quoted
On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 05:47 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 03:35 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
quoted
On 03/10/2015 03:17 PM, Daniel Vetter wrote:
quoted
On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
driver"
+ depends on DRM
+ select DRM_KMS_HELPER
+ select DRM_KMS_FB_HELPER
+ select FB_SYS_FILLRECT
+ select FB_SYS_COPYAREA
+ select FB_SYS_IMAGEBLIT
+ select FB_SYS_FOPS
+ select FB_CFB_FILLRECT
+ select FB_CFB_COPYAREA
+ select FB_CFB_IMAGEBLIT
+ default y
+ help
+ Choose this option if you have a need for the legacy
fbdev
+ support. Note that this support also provide the linux
console
+ support on top of your modesetting driver.
Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
DRM_KMS_FB_HELPER selects that for us, right?
Hm right I've missed that. Reminds me that you need one more
patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all
drm
drivers. Otherwise this knob here won't work by default if you
e.g. select
radeon. In general we can't mix explicit options with menu
entries with a
select.
I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff
internally in
their respective xyz_fbdev.c files.
But with the stubbed out functions that should work, right? Why
doesn't
it?
There are still calls to functions from fb core like fb_set_suspend
and
register_framebuffer which aren't covered by the drm fb helper
functions.
Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?
There are a handful of fb core functions which are called by drm
drivers:
fb_alloc_cmap/fb_dealloc_cmap
fb_sys_read/fb_sys_write
register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers
fb_set_suspend
fb_deferred_io_init/fb_deferred_io_cleanup
framebuffer_alloc/framebuffer_release
Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into
drm_fb_helper.h
2. Then we add stubs for these functions in drm_fb_helper.h, like this
#if defined(CONFIG_FB)
#include <linux/fb.h>
#else
/* static inline stubs for all the fb stuff used by kms drivers */
#endif
Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.
I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.
I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h
itself,
but that seemed a bit too intrusive.
This is what I'm currently doing:
- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap
would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.
- For the rest of the functions that are sparsely used, I was
considering
making very simple drm_fb_* wrapper functions. Something like:
void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
if (helper->fbdev)
fb_deferred_io_init(helper->fbdev);
}
We could have all fb calls called within drm_fb_helper.c, creating
drm_fb_helper_* stub functions would then be an easier task. What do you
think?
That's actually an option I considered, but I hoped we could do it with
less work. If this indeed works and you can create the patch that would
be
awesome.
Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
Hm, the point of the kconfig is to not require all the legacy baggage
from fbdev. But I guess a module option could be added later on too.
bochs has it too.
I think the option would primarily be useful for testing. I've often
needed to test modesetting code without fbdev getting in the way and the
only way to currently do that is by recompiling with legacy fbdev
disabled. The option would allow an fbdev-enabled kernel to be used but
disable the fbdev code if desired.
Thierry
Hm, the point of the kconfig is to not require all the legacy baggage
from fbdev. But I guess a module option could be added later on too.
bochs has it too.
I think the option would primarily be useful for testing. I've often
needed to test modesetting code without fbdev getting in the way and the
only way to currently do that is by recompiling with legacy fbdev
disabled. The option would allow an fbdev-enabled kernel to be used but
disable the fbdev code if desired.
and for debugging.. when things are going wrong it's nice for the
first modeset to not happen under console_lock ;-)
BR,
-R