[v3,0/3] drm,fbdev: Fix module dependencies

Message

Thomas Zimmermann Dec. 16, 2024, 7:42 a.m. UTC

Fix the dependencies among the various graphics modules.

Before addressing the FB_CORE issue, patch 1 first resolves a problem
with BACKLIGHT_CLASS_DEVICE. A number of fbdev drivers select it, which
results in a recursive-dependency error after patch has been applied.
Making these drivers (or parts of them) depend on BACKLIGHT_CLASS_DEVICE
fixes this.

Patch 2 selects FB_CORE for DRM_GEM_DMA_HELPER and DRM_TTM_HELPER.
This is necessary with the recently added DRM client library.

Patch 3 is the second half of the patch provided by Arnd at [1]. It
could not yet be merged because of the issues fixed by patch 1.

Side note: For the majority of graphics drivers, backlight functionality
depends on BACKLIGHT_CLASS_DEVICE. In a few cases drivers select the
Kconfig token automatically. These drivers should be updated to depend
on the token as well, such that backlight functionality is fully user-
controlled.

v3:
- Fix PMAC_BACKLIGHT case (Christophe)
v2:
- s/BACKLIGHT_DEVICE_CLASS/BACKLIGHT_CLASS_DEVICE (Helge)
- Fix fbdev driver-dependency corner case (Arnd)

[1] https://patchwork.freedesktop.org/series/141411/

Arnd Bergmann (1):
  drm: rework FB_CORE dependency

Thomas Zimmermann (2):
  fbdev: Fix recursive dependencies wrt BACKLIGHT_CLASS_DEVICE
  drm/fbdev: Select FB_CORE dependency for fbdev on DMA and TTM

 arch/powerpc/configs/pmac32_defconfig |  1 +
 arch/powerpc/configs/ppc6xx_defconfig |  1 +
 drivers/auxdisplay/Kconfig            |  2 +-
 drivers/gpu/drm/Kconfig               |  3 +++
 drivers/macintosh/Kconfig             |  1 +
 drivers/staging/fbtft/Kconfig         |  1 +
 drivers/video/fbdev/Kconfig           | 18 +++++++++++++-----
 drivers/video/fbdev/core/Kconfig      |  3 +--
 8 files changed, 22 insertions(+), 8 deletions(-)

Comments

Arnd Bergmann Dec. 16, 2024, 10:12 a.m. UTC | #1

On Mon, Dec 16, 2024, at 08:42, Thomas Zimmermann wrote:
> Fix the dependencies among the various graphics modules.
>
> Before addressing the FB_CORE issue, patch 1 first resolves a problem
> with BACKLIGHT_CLASS_DEVICE. A number of fbdev drivers select it, which
> results in a recursive-dependency error after patch has been applied.
> Making these drivers (or parts of them) depend on BACKLIGHT_CLASS_DEVICE
> fixes this.
>
> Patch 2 selects FB_CORE for DRM_GEM_DMA_HELPER and DRM_TTM_HELPER.
> This is necessary with the recently added DRM client library.
>
> Patch 3 is the second half of the patch provided by Arnd at [1]. It
> could not yet be merged because of the issues fixed by patch 1.
>
> Side note: For the majority of graphics drivers, backlight functionality
> depends on BACKLIGHT_CLASS_DEVICE. In a few cases drivers select the
> Kconfig token automatically. These drivers should be updated to depend
> on the token as well, such that backlight functionality is fully user-
> controlled.
>
> v3:
> - Fix PMAC_BACKLIGHT case (Christophe)
> v2:

The patches look good to me. I've had a slightly different version
in my randconfig test tree and have replaced it with yours now
to do some more regression testing, but I expect this to be fine.

Reviewed-by: Arnd Bergmann <[e-mail]>