Thread (7 messages) 7 messages, 5 authors, 2018-02-26

Re: [PATCH] drm/pl111: Remove reverse dependency on DRM_DUMB_VGA_DAC

From: Eric Anholt <hidden>
Date: 2018-02-22 20:10:46
Also in: dri-devel

Thierry Reding [off-list ref] writes:
quoted hunk ↗ jump to hunk
From: Thierry Reding <redacted>

DRM_DUMB_VGA_DAC is a user-visible symbol. Selecting it can cause unmet
direct dependencies such as this (on i386, randconfig):

	warning: (DRM_PL111) selects DRM_DUMB_VGA_DAC which has unmet direct dependencies (HAS_IOMEM && DRM && DRM_BRIDGE && OF)

This is because DRM_DUMB_VGA_DAC depends on OF while DRM_PL111 does not.
It does indirectly depend on OF via the ARM and ARM64 dependencies, but
since it can also be enabled under COMPILE_TEST, randconfig can find a
case where DRM_PL111 is selected without pulling in OF and not meeting
the dependency for DRM_DUMB_VGA_DAC.

Since select is "heavy handed", DRM_DUMB_VGA_DAC is going to be enabled
regardless of the above warning and causes the following build error:

	../drivers/gpu/drm/bridge/dumb-vga-dac.c: In function 'dumb_vga_probe':
	../drivers/gpu/drm/bridge/dumb-vga-dac.c:207:13: error: 'struct drm_bridge' has no member named 'of_node'
	  vga->bridge.of_node = pdev->dev.of_node;

See Documentation/kbuild/kconfig-language.txt, "reverse dependencies".

Fixes: 49f81d80ab84 ("drm/pl111: Support handling bridge timings")
Reported-by: Randy Dunlap <redacted>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Archit Taneja <redacted>
Cc: Eric Anholt <redacted>
Signed-off-by: Thierry Reding <redacted>
---
 drivers/gpu/drm/pl111/Kconfig | 1 -
 1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/pl111/Kconfig b/drivers/gpu/drm/pl111/Kconfig
index 82cb3e60ddc8..e5e2abd66491 100644
--- a/drivers/gpu/drm/pl111/Kconfig
+++ b/drivers/gpu/drm/pl111/Kconfig
@@ -8,7 +8,6 @@ config DRM_PL111
 	select DRM_GEM_CMA_HELPER
 	select DRM_BRIDGE
 	select DRM_PANEL_BRIDGE
-	select DRM_DUMB_VGA_DAC
 	select VT_HW_CONSOLE_BINDING if FRAMEBUFFER_CONSOLE
 	help
 	  Choose this option for DRM support for the PL111 CLCD controller.
-- 
2.15.1
Reviewed-by: Eric Anholt <redacted>
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