Re: [PATCH] firmware/sysfb: Fix wrong stride when bits-per-pixel is calculated
From: Javier Martinez Canillas
Date: Thu Apr 13 2023 - 02:56:08 EST
"Pierre Asselin" <pa@xxxxxxxxx> writes:
[...]
> [ 3.343433] sysfb: si->rsvd_size 0 si->rsvd_pos 0
Thanks for confirming this. I was expected that as mentioned since it was
the only reasonable explanation for your problem.
[...]
> What if _depth is low but the rsvd_ are right ?
> Then _width and _linelength would be inconsistent with _depth but
> consistent with the recomputed bits_per_pixel ? How many ways can the
> firmware lie ?
>
I don't know. But in your case the firmware is not reporting the mode
correctly since it is setting a framebuffer of 1024x768 and xRGB but
is not reporting si->rsvd_size=8 and si->rsvd_pos=24 as it should.
One option is to have a DMI match table similar to what we already have
for EFI machines in drivers/firmware/efi/sysfb_efi.c but also for BIOS.
The question then is if we can trust other systems to report a proper
rsvd_size and rsvd_pos...
> We need more testers, don't we ?
>
It's tricky, yes.
--
Best regards,
Javier Martinez Canillas
Core Platforms
Red Hat