Kyösti Mälkki has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/31325 )
Change subject: lenovo/g505s/Kconfig: Set framebuffer graphics mode to VESA 118h mode ......................................................................
Patch Set 4:
67:Option ROM run done 18,020,791 (207,775) 70:device setup done 18,020,875 (84) 75:cbmem post 18,090,768 (69,892) 80:write tables 18,090,772 (3) 85:finalize chips 18,095,156 (4,383) 90:load payload 18,095,161 (4) 15:starting LZMA decompress (ignore for x86) 18,095,496 (335) 16:finished LZMA decompress (ignore for x86) 18,125,067 (29,571) 99:selfboot jump 18,125,101 (33)
If we trust the stamps, that's like 100ms the splash would be shown. On 50hz screen that's five frames. Depending of platform I guess, does OPROM control backlight PWM? Assuming that OPROM may also exit before backlight is really lit, you are left with few frames until payload will wipe the framebuffer.
That's the reasoning why coreboot bootsplash is much ado about nothing.