When using the DRM draw support, the only way to check if a color can be
converted from XRGB8888 to a target format is currently to attempt an
actual conversion using drm_draw_color_from_xrgb8888(). This function
however will print a WARN the first time a conversion cannot be
performed, leading to two potential issues:
- a WARN is emitted without a real reason if the caller is only
attempting a conversion to check if a format can be supported (which
is the case for two of the current user of this API);
- a failing call following the first one is not emitting a WARN, but a
"valid" color value (0x00000000) is returned nevertheless.
The first issue was observed while using drm_log on a Beagleplay, which
lists AR12 as the first format for its HDMI modesets.
The target of this patch set is to improve this situation; the first
patch introduces a new API devoted only to check if a conversion from
XRGB8888 to the specified format can be performed, while the other two
substitute drm_draw_color_from_xrgb8888() with this new API in the
current users (drm_panic and drm_log) where relevant.
Signed-off-by: Francesco Valla <francesco@valla.it>
---
Changes in v3:
- Collected R-b tags from Jocelyn (thank you!)
- Link to v2: https://lore.kernel.org/r/20251014-drm_draw_conv_check-v2-0-05bef3eb06fb@valla.it
Changes in v2:
- Moved to dedicated switch cases in separate functions instead of
single one inside common function.
- Fix copy-paste error in commit message.
Link to v1: https://lore.kernel.org/r/20251005-drm_draw_conv_check-v1-0-9c814d9362f6@valla.it
---
Francesco Valla (3):
drm/draw: add drm_draw_can_convert_from_xrgb8888
drm/log: avoid WARN when searching for usable format
drm/panic: avoid WARN when checking format support
drivers/gpu/drm/clients/drm_log.c | 2 +-
drivers/gpu/drm/drm_draw.c | 29 +++++++++++++++++++++++++++++
drivers/gpu/drm/drm_draw_internal.h | 2 ++
drivers/gpu/drm/drm_panic.c | 2 +-
4 files changed, 33 insertions(+), 2 deletions(-)
---
base-commit: ea1013c1539270e372fc99854bc6e4d94eaeff66
change-id: 20251003-drm_draw_conv_check-9cc3050ebd57
Best regards,
--
Francesco Valla <francesco@valla.it>