From: Pierre Asselin <pa@xxxxxxxxx>
[ Upstream commit 1b617bc93178912fa36f87a957c15d1f1708c299 ]
Some legacy BIOSes report no reserved bits in their 32-bit rgb mode,
breaking the calculation of bits_per_pixel in commit f35cd3fa7729
("firmware/sysfb: Fix EFI/VESA format selection"). However they report
lfb_depth correctly for those modes. Keep the computation but
set bits_per_pixel to lfb_depth if the latter is larger.
v2 fixes the warnings from a max3() macro with arguments of different
types; split the bits_per_pixel assignment to avoid uglyfing the code
with too many typecasts.
v3 fixes space and formatting blips pointed out by Javier, and change
the bit_per_pixel assignment back to a single statement using two casts.
v4 go back to v2 and use max_t()
Signed-off-by: Pierre Asselin <pa@xxxxxxxxx>
Fixes: f35cd3fa7729 ("firmware/sysfb: Fix EFI/VESA format selection")
Link: https://lore.kernel.org/r/4Psm6B6Lqkz1QXM@xxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20230412150225.3757223-1-javierm@xxxxxxxxxx
Tested-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20230419044834.10816-1-pa@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/firmware/sysfb_simplefb.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c
index 82c64cb9f5316..74363ed7501f6 100644
--- a/drivers/firmware/sysfb_simplefb.c
+++ b/drivers/firmware/sysfb_simplefb.c
@@ -51,7 +51,8 @@ __init bool sysfb_parse_mode(const struct screen_info *si,
*
* It's not easily possible to fix this in struct screen_info,
* as this could break UAPI. The best solution is to compute
- * bits_per_pixel here and ignore lfb_depth. In the loop below,
+ * bits_per_pixel from the color bits, reserved bits and
+ * reported lfb_depth, whichever is highest. In the loop below,
* ignore simplefb formats with alpha bits, as EFI and VESA
* don't specify alpha channels.
*/
@@ -60,6 +61,7 @@ __init bool sysfb_parse_mode(const struct screen_info *si,
si->green_size + si->green_pos,
si->blue_size + si->blue_pos),
si->rsvd_size + si->rsvd_pos);
+ bits_per_pixel = max_t(u32, bits_per_pixel, si->lfb_depth);
} else {
bits_per_pixel = si->lfb_depth;
}
--
2.39.2
