linux-kernel - Re: [PATCH] firmware/sysfb: Fix wrong stride when bits-per-pixel is calculated

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Message-ID: <2e07f818ccdff7023a060e732d7c4ef6.squirrel@mail.panix.com>
Date:   Wed, 12 Apr 2023 12:18:17 -0400
From:   "Pierre Asselin" <pa@...ix.com>
To:     "Javier Martinez Canillas" <javierm@...hat.com>
Cc:     linux-kernel@...r.kernel.org, "Pierre Asselin" <pa@...ix.com>,
        "Jocelyn Falempe" <jfalempe@...hat.com>,
        "Daniel Vetter" <daniel.vetter@...ll.ch>,
        dri-devel@...ts.freedesktop.org,
        "Thomas Zimmermann" <tzimmermann@...e.de>,
        "Javier Martinez Canillas" <javierm@...hat.com>,
        "Ard Biesheuvel" <ardb@...nel.org>,
        "Hans de Goede" <hdegoede@...hat.com>
Subject: Re: [PATCH] firmware/sysfb: Fix wrong stride when bits-per-pixel is
 calculated

> The commit f35cd3fa7729 ("firmware/sysfb: Fix EFI/VESA format selection")
> fixed format selection, by calculating the bits-per-pixel instead of just
> using the reported color depth.
>
> But unfortunately this broke some modes because the stride is always set
> to the reported line length (in bytes), which could not match the actual
> stride if the calculated bits-per-pixel doesn't match the reported depth.
>
> Fixes: f35cd3fa7729 ("firmware/sysfb: Fix EFI/VESA format selection")
> Reported-by: Pierre Asselin <pa@...ix.com>
> Signed-off-by: Javier Martinez Canillas <javierm@...hat.com>
> ---
>
>  drivers/firmware/sysfb_simplefb.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/sysfb_simplefb.c
> b/drivers/firmware/sysfb_simplefb.c
> index 82c64cb9f531..5dc23e57089f 100644
> --- a/drivers/firmware/sysfb_simplefb.c
> +++ b/drivers/firmware/sysfb_simplefb.c
>
> [patch elided]

NOOOOOO !  The 1024x768x32 screen is all garbled.
(gfxpayload=keep, gfxpayload=1024x768x32 or vga=0x318).

The other modes work as before (but the dmesg has less information;
I'll investigate.)