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From: Javier Martinez Canillas <javierm@redhat.com>
To: Pierre Asselin <pa@panix.com>
Cc: Pierre Asselin <pa@panix.com>,
	Jocelyn Falempe <jfalempe@redhat.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Hans de Goede <hdegoede@redhat.com>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	Ard Biesheuvel <ardb@kernel.org>
Subject: Re: [PATCH] firmware/sysfb: Fix wrong stride when bits-per-pixel is calculated
Date: Thu, 13 Apr 2023 08:54:58 +0200	[thread overview]
Message-ID: <87r0souv99.fsf@minerva.mail-host-address-is-not-set> (raw)
In-Reply-To: <9e6fff69b09b36cbdd96499cd0015154.squirrel@mail.panix.com>

"Pierre Asselin" <pa@panix.com> 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


      parent reply	other threads:[~2023-04-13  6:56 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-12 15:02 Javier Martinez Canillas
2023-04-12 16:18 ` Pierre Asselin
2023-04-12 17:31   ` Javier Martinez Canillas
2023-04-12 18:12     ` Pierre Asselin
2023-04-12 18:24       ` Javier Martinez Canillas
2023-04-12 18:51         ` Pierre Asselin
2023-04-12 21:04           ` Javier Martinez Canillas
2023-04-12 21:40             ` Javier Martinez Canillas
2023-04-12 21:53               ` Pierre Asselin
2023-04-12 22:09                 ` Javier Martinez Canillas
2023-04-12 23:13                   ` Pierre Asselin
2023-04-13  1:13                     ` Pierre Asselin
2023-04-13  1:34                       ` Pierre Asselin
2023-04-17  8:15                         ` Thomas Zimmermann
2023-04-17  8:58                           ` Javier Martinez Canillas
2023-04-17  9:15                             ` Thomas Zimmermann
2023-04-17  9:29                               ` Javier Martinez Canillas
2023-04-13  7:08                       ` Javier Martinez Canillas
2023-04-13 16:24                         ` Pierre Asselin
2023-04-13 16:34                           ` Javier Martinez Canillas
2023-04-13 17:17                         ` Pierre Asselin
2023-04-13 18:04                           ` Javier Martinez Canillas
2023-04-13  6:54                     ` Javier Martinez Canillas [this message]

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