[PATCH v3 01/13] firmware/sysfb: Fix EFI/VESA format selection

[Pierre Asselin]

> Can you please share you grub config file? It seems that is set to
> GRUB_GFXMODE=1024x768x32 but the actual mode is set to 1024x768x24 ?

Okay, but you'll be sorry...  The gfxmode is set to "keep" in all the
entries.  https://www.panix.com/~pa/linux-6.3-simplefb/grub.cfg .

The "TEST" entry was used to bisect.  The "PRE-TEST" was to set things
up, to receive the bzImages compiled on a faster machine. Now I boot
the "Linux 6.3.0-rc5-x86".


> That is, it fails when the picked format is DRM_FORMAT_RGB8888 but
> works when is DRM_FORMAT_XRGB888. I can't spot any error in Thomas'
> patch so I wonder if the problem is with what grub is passing to the
> kernel.
>
> The mentioned vga=0x318 workaround that you mentioned makes the mode
> passed to match the selected DRM_FORMAT_RGB888 which I guess is why
> that worked for you.

All right, I did a series of reboots, editing the grub command line
to change the "gfxpayload=" grub option or the "vga=" kernel option.
In each case I captured the output of
  "dmesg | egrep -i 'fbcon|console|fb0|frameb|simple|vga|vesa'

https://www.panix.com/~pa/linux-6.3-simplefb/selected-modes

(D'oh.  My script printed "vga=vga=" twice when that option was set.
Good enough as is.)

Note the difference in linelength= between the bad and good r8g8b8.
Does it mean anything ?
 (bad)> format=r8g8b8, mode=1024x768x24, linelength=4096
(good)> format=r8g8b8, mode=1024x768x24, linelength=3072