Re: 5.15 regression: CONFIG_SYSFB_SIMPLEFB breaks console scrolling

[Thorsten Leemhuis <regressions@leemhuis.info>]

Hi, this is your Linux kernel regression tracker speaking.

On 16.11.21 05:52, Harald Dunkel wrote:
> 
> if I enable CONFIG_SYSFB_SIMPLEFB in 5.15.2 and use grub's default
> configuration
> (Debian sid amd64), then a few lines at the bottom of /dev/tty1 including
> login prompt are off-screen. Scrolling is broken. I can login, though.
> 
> Enabling GRUB_TERMINAL=console in grub doesn't make a difference. Using
> the same kernel except for CONFIG_SYSFB_SIMPLEFB the problem is gone.
> 
> Graphics card is a GeForce GTX 1650. I tried with both CONFIG_DRM_NOUVEAU
> and proprietary graphics drivers disabled.
> 
> Attached you can find the config file. Please mail if I can help to track
> this problem down.

Thx for the report. I'm not totally sure if this is a regression, as
that's a new config option. But it might be one considered a successor
to an older one, hence it might count as regression. Adding two
developers and a mailing list to the CC, hopefully someone can clarify.

TWIMC: To be sure this issue doesn't fall through the cracks unnoticed,
I'm adding it to regzbot, my Linux kernel regression tracking bot:

#regzbot ^introduced 8633ef82f101c040427b57d4df7b706261420b94
#regzbot title CONFIG_SYSFB_SIMPLEFB breaks console scrolling
#regzbot ignore-activity

Ciao, Thorsten, your Linux kernel regression tracker.

P.S.: If you want to know more about regzbot, check out its
web-interface, the getting start guide, and/or the references documentation:

https://linux-regtracking.leemhuis.info/regzbot/
https://gitlab.com/knurd42/regzbot/-/blob/main/docs/getting_started.md
https://gitlab.com/knurd42/regzbot/-/blob/main/docs/reference.md

The last two documents will explain how you can interact with regzbot
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Hint for the reporter: when reporting a regression it's in your interest
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regression gets on the radar of regzbot and the regression tracker.
That's in your interest, as they will make sure the report won't fall
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Hint for developers: you normally don't need to care about regzbot, just
fix the issue as you normally would. Just remember to include a 'Link:'
tag to the report in the commit message, as explained in
Documentation/process/submitting-patches.rst
That aspect was recently was made more explicit in commit 1f57bd42b77c:
https://git.kernel.org/linus/1f57bd42b77c