Thomas Zimmermann <tzimmermann@xxxxxxx> wrote: > Select color format for EFI/VESA firmware scanout buffer from the > number of bits per pixel and the position of the individual color > components. Fixes the selected format for the buffer in several odd > cases. For example, XRGB1555 has been reported as ARGB1555 because > of the different use of depth and transparency in VESA and Linux. > > Bits-per-pixel is always the pixel's raw number of bits; including > alpha and filler bits. It is preferred over color depth, which has a > different meaning among various components and standards. > > Also do not compare reserved bits and transparency bits to each other. > These values have different meanings, as reserved bits include filler > bits while transparency does not. > > Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> > Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> > --- > drivers/firmware/sysfb_simplefb.c | 43 ++++++++++++++++++++++++++----- > 1 file changed, 37 insertions(+), 6 deletions(-) > [patch elided] Starting at linux-6.3-rc1 my simplefb picks the wrong mode and garbles the display This is on a 16-year old i686 laptop. I can post lshw or dmidecode output if it helps. The issue is still present in 6.3-rc5. Screenshot: https://www.panix.com/~pa/linux-6.3-simplefb/bug-simplefb-bad.jpg Compare: https://www.panix.com/~pa/linux-6.3-simplefb/bug-simplefb-good.jpg This happens during early boot. Grub picks a 1024x786 mode and leaves it for the kernel. The screenshots are from a rescueshell in early userspace. The dmesg excerpts at the bottom might give some clues. I bisected it to f35cd3fa77293c2cd03e94b6a6151e1a7d9309cf firmware/sysfb: Fix EFI/VESA format selection which is this patch. It's not the end of the world: 1) I have a workaround, booting with vga=0x318; 2) the screen is usable even without the workaround; 3) the final fbcon driver takes over after the switch_root. Nevertheless, it would be nice to get this fixed this before 6.3. I may be the only one with this problem. Who else runs -rc kernels on such old hardware ? I'll answer questions as best I can and test any patches thrown at me. --pa
