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. Recompute bits_per_pixel from the color and reserved bit numbers and positions, but also from lfb_depth, keeping the larger result. Link: https://lore.kernel.org/r/4Psm6B6Lqkz1QXM@xxxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20230412150225.3757223-1-javierm@xxxxxxxxxx Fixes: f35cd3fa7729 [firmware/sysfb: Fix EFI/VESA format selection] Signed-off-by: Pierre Asselin <pa@xxxxxxxxx> --- drivers/firmware/sysfb_simplefb.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c index 82c64cb9f531..05dc25a524c8 100644 --- a/drivers/firmware/sysfb_simplefb.c +++ b/drivers/firmware/sysfb_simplefb.c @@ -51,15 +51,17 @@ __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. */ if (si->lfb_depth > 8) { - bits_per_pixel = max(max3(si->red_size + si->red_pos, + bits_per_pixel = max3(max3(si->red_size + si->red_pos, si->green_size + si->green_pos, si->blue_size + si->blue_pos), - si->rsvd_size + si->rsvd_pos); + si->rsvd_size + si->rsvd_pos, + si->lfb_depth); } else { bits_per_pixel = si->lfb_depth; } -- 2.39.2
