linux-stable.git/drivers/gpu/drm/sysfb/drm_sysfb_helper.h, branch linux-rolling-stable

drm/sysfb: Return errno code from drm_sysfb_get_visible_size()

2026-08-03T09:25:40+00:00

commit 7bab0f09d753f098977bbba3955d694c2e2c25da upstream.

Change the return type of drm_sysfb_get_visible_size() to s64 so
that it returns a possible errno code from _get_validated_size0().
Fix callers to handle the errno code.

The currently returned unsigned type converts an errno code to a
very large size value, which drivers interpret as visible size of
the system framebuffer. Later efforts to reserve the framebuffer
resource fail.

The bug has been present since efidrm and vesadrm got merged. It
was then part of each driver.

Signed-off-by: Thomas Zimmermann 
Fixes: 32ae90c66fb6 ("drm/sysfb: Add efidrm for EFI displays")
Fixes: a84eb6abe2b6 ("drm/sysfb: Add vesadrm for VESA displays")
Reviewed-by: Javier Martinez Canillas 
Cc: Thomas Zimmermann 
Cc: Javier Martinez Canillas 
Cc: dri-devel@lists.freedesktop.org
Cc:  # v6.16+
Link: https://patch.msgid.link/20260618084327.46567-4-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman

drm/sysfb: Generalize pixel-format matching

2026-02-20T13:38:23+00:00

Provide drm_sysfb_get_format(), a helper that finds a specific DRM
format from a list of pixel formats. The new function builds upon
drm_sysfb_get_format_si(), which finds the DRM format from a given
instance of struct screen_info. Now get the screen_info's pixel format
in the caller. Allows for matching pixel formats in drivers without
screen_info.

Convert the callers in efidrm and vesadrm to the new interface.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Acked-by: Julius Werner 
Link: https://patch.msgid.link/20260217155836.96267-11-tzimmermann@suse.de

drm/sysfb: Remove duplicate declarations

2026-01-14T10:03:56+00:00

Commit 6046b49bafff ("drm/sysfb: Share helpers for integer validation")
and commit e8c086880b2b ("drm/sysfb: Share helpers for screen_info
validation") added duplicate function declarations. Remove the latter
ones.

Signed-off-by: Thomas Zimmermann 
Fixes: e8c086880b2b ("drm/sysfb: Share helpers for screen_info validation")
Cc: Thomas Zimmermann 
Cc: Javier Martinez Canillas 
Cc: dri-devel@lists.freedesktop.org
Cc:  # v6.16+
Reviewed-by: Javier Martinez Canillas 
Link: https://patch.msgid.link/20260108145058.56943-7-tzimmermann@suse.de

drm/sysfb: Lookup blit function during atomic check

2025-09-23T13:06:06+00:00

Some configurations of sysfb outputs require format conversion from
framebuffer to scanout buffer. It is a driver bug if the conversion
helper is missing, yet it might happen on odd scanout formats. The old
code, based on drm_fb_blit(), only detects this situation during the
commit's hardware update, which is too late to abort the update.

Lookup the correct blit helper as part of the check phase. Then store
it in the sysfb plane state. Allows for detection of a missing helper
before the commit has started. Also avoids drm_fb_blit()'s large switch
statement on each updated scanline. Only a single lookup has to be done.

The lookup is in drm_sysfb_get_blit_func(), which only tracks formats
supported by sysfb drivers.

The lookup happens in sysfb's begin_fb_access helper instead of its
atomic_check helper. This allows vesadrm, and possibly other drivers,
to implement their own atomic_check without interfering with blit
lookups. Vesadrm implements XRGB8888 on top of R8 formats with the
help of the atomic_check. Doing the blit lookup in begin_fb_access then
always uses the correct CRTC format on all drivers.

v2:
- vesadrm: use drm_sysfb_plane_helper_begin_fb_access()
- fix type in commit description (Javier)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250918154207.84714-3-tzimmermann@suse.de

drm/sysfb: Add custom plane state

2025-09-23T13:06:05+00:00

The plane-state type struct drm_sysfb_plane_state will store the
helper for blitting to the scanout buffer.

v2:
- add variable for duplicated shadow-plane state (Javier)
- fix build error

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250918154207.84714-2-tzimmermann@suse.de

drm/sysfb: Blit to CRTC destination format

2025-08-26T07:54:17+00:00

Use the color format stored in struct drm_sysfb_crtc_state for
color-format conversion instead of the scanout-buffer format
announced by firmware. Currently, both values are identical.

This will allow drivers to modify the CRTC's input format to a
certain extend. Specifically, vesadrm will be able to display RGB
framebuffers when the scanout buffer is of C8 format. With color-
format conversion to RGB332 and correct setup of the C8 palette,
displaying XRGB8888-based buffers under C8 can be achieved.

v2:
- refer to RGB332 as CRTC input format

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250714151513.309475-5-tzimmermann@suse.de

drm/format-helper: Move drm_fb_build_fourcc_list() to sysfb helpers

2025-06-18T08:46:03+00:00

Only sysfb drivers use drm_fb_build_fourcc_list(). Move the function
to sysfb helpers and rename it accordingly. Update drivers and tests.

v3:
- update naming in tests
v2:
- select DRM_SYSFB_HELPER (kernel test robot)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: José Expósito 
Acked-by: Maxime Ripard 
Acked-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250616083846.221396-4-tzimmermann@suse.de

drm/sysfb: Share helpers for screen_info validation

2025-04-14T08:16:14+00:00

Share efidrm's and vesadrm's validation of struct screen_info in
shared helpers. Update the drivers.

Most validation helpers test individual values against limits and
can be shared as they are. For color formats, a common helper looks
up the correct DRM format info from a driver-provided list of color
formats.

These screen_info helpers are only available if CONFIG_SCREEN_INFO
has been selected, as done by efidrm and vesadrm.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250410083834.10810-4-tzimmermann@suse.de

drm/sysfb: Share helpers for integer validation

2025-04-14T08:16:13+00:00

Provide sysfb helpers for validating framebuffer integer values
against limits. Update drivers. If a driver did not specify a limit
for a certain value, use INT_MAX.

v2:
- declare module information near EOF (Javier)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250410083834.10810-3-tzimmermann@suse.de

drm/sysfb: Split source file

2025-04-14T08:16:12+00:00

Split drm_sysfb_helper.c into two source files. There's now one
source file for the mode-setting pipeline and one source file for
module meta data. Prepares for adding additional source code to
sysfb helpers.

v2:
- fix typo in commit message (Javier)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250410083834.10810-2-tzimmermann@suse.de