linux-kernel - Re: Fwd: absent both plymouth, and video= on linu lines, vtty[1-6] framebuffers produce vast raster right and bottom borders on the larger resolution of two displays

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Message-ID: <585f36f8-431a-e929-0a04-ffb65f02e9df@gmail.com>
Date:   Thu, 25 May 2023 17:55:45 +0700
From:   Bagas Sanjaya <bagasdotme@...il.com>
To:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Regressions <regressions@...ts.linux.dev>,
        Linux Framebuffer <linux-fbdev@...r.kernel.org>,
        DRI Development List <dri-devel@...ts.freedesktop.org>,
        Linux Nouveau/NVIDIA <nouveau@...ts.freedesktop.org>,
        Linux Stable <stable@...r.kernel.org>
Cc:     Daniel Vetter <daniel@...ll.ch>, Helge Deller <deller@....de>,
        Antonino Daplas <adaplas@...il.com>,
        Ben Skeggs <bskeggs@...hat.com>,
        Karol Herbst <kherbst@...hat.com>,
        Lyude Paul <lyude@...hat.com>,
        Felix Miata <mrmazda@...thlink.net>
Subject: Re: Fwd: absent both plymouth, and video= on linu lines, vtty[1-6]
 framebuffers produce vast raster right and bottom borders on the larger
 resolution of two displays

On 5/25/23 17:52, Bagas Sanjaya wrote:
> Hi,
> 
> I notice a regression report on Bugzilla [1]. Quoting from it:
> 
>> Original Summary:
>> absent both plymouth, and video= on linu lines, vtty[1-6] framebuffers produce vast raster right and bottom borders on the larger resolution of two displays
>>
>> To reproduce:
>> 1-connect two unequal native resolution displays to a Tesla or Firmi GPU
>> 2-don't have plymouth in use (I don't ever have it installed, so don't know whether it impacts)
>> 3-don't include e.g. video=1440x900@60 directive on Grub's linu lines
>> 4-boot Tumbleweed or Fedora 38
>> 5-switch to a vtty, e.g. Ctrl-Alt-F3
>>
>> Actual behavior:
>> 1-Both displays utilize the resolution (same pixel grid) of the lower resolution display
>> 2-Lower resolution display behaves as expected (light text on black background)
>> 3-Higher resolution display uses same pixels as lower resolution display, with light text on black background, leaving right side and bottom raster instead of black
>>
>> Expected behavior:
>> 1-Both displays utilize the resolution (same pixel grid) of the lower resolution display
>> 2-Lower resolution display behaves as expected
>> 3-Entire higher resolution display's background is black instead of portions in raster
>>
>> Workaround: add e.g. video=1440x900@60 to Grub's linu lines, which causes both displays to use the same nominal mode on the full display space.
>>
>> Typical other linu line options:
>> noresume consoleblank=0 net.ifnames=0 ipv6.disable=1 preempt=full mitigations=none
>>
>> My Tesla has HDMI and DVI outputs, tested with 1920x1200 and 1680x1050 displays.
>> My Fermi has dual DisplayPort, tested with 2560x1440 and 1680x1050 displays.
>> Occurs Tumbleweed with 6.3.2 and 6.2.12 kernel-default, and with 6.2.15 on Fedora 38, and (partially with Tesla, right side only) with 6.2.12 and 6.3.3 on Mageia 9.
>> Does not occur with 6.1.12 kernel-default on NVidia, or with AMD Caicos (Terascale2) GPU, or with Intel Eaglelake GPU.
>> Tested only on legacy booting (no UEFI support).
>> Others might describe what I call "raster" as multicolored snow.
> 
> See bugzilla for the full thread and attached dmesg.
> 
> Anyway, I'm adding it to regzbot:
> 
> #regzbot introduced: v6.1.12..v6.2.12
> #regzbot title: vast raster right and bottom borders on larger display (two displays with inequal resolution) unless forcing resolution with video= parameter
> 

Oops, I forget to add bugzilla link:

#regzbot introduced: v6.1.12..v6.2.12 https://bugzilla.kernel.org/show_bug.cgi?id=217479
#regzbot from: Felix Miata <mrmazda@...thlink.net>

Thanks.

-- 
An old man doll... just what I always wanted! - Clara