Re: [PATCH 2/2] Revert "fbcon: Disable accelerated scrolling"

From: Thomas Zimmermann
Date: Wed Jan 19 2022 - 10:37:05 EST


Hi

Am 19.01.22 um 16:05 schrieb Sven Schnelle:
Daniel Vetter <daniel@xxxxxxxx> writes:

On Wed, Jan 19, 2022 at 3:01 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
Irrespective of this code being buggy or not buggy I think the bigger
pictures, and really the reason I want to see as much code ditched
from the fbdev/fbcon stack as we possible can, are very clear:

- it's full of bugs
- there's no test coverage/CI to speak of
- it's very arcane code which is damn hard to understand and fix issues within
- the locking is busted (largely thanks to console_lock, and the
effort to make that reasonable from -rt folks has been slowly creeping
forward for years).

Iow this subsystem is firmly stuck in the 90s, and I think it's best
to just leave it there. There's also not been anyone actually capable
and willing to put in the work to change this (pretty much all actual
changes/fixes have been done by drm folks anyway, like me having a
small pet project to make the fbdev vs fbcon locking slightly less
busted).

Saying it's stuck in the 90ies, and actively trying to prevent
Helge from taking over maintainership at the same time looks odd.

The issues are in the design itself. It's impossible to model today's hardware and constraints with fbdev. It's impossible to change configuration in a reliable way (i.e., what DRM calls atomic). Fbdev mmaps plain video ram to userspace, which is one of the reasons why DRM's fbdev support is hard to improve.

I think Helge should at least get a chance to fix the issues. If the
state is still the same in a year or so it should be discussed again.

You cannot fix that in 10yrs.


The other side is that being a maintainer is about collaboration, and
this entire fbdev maintainership takeover has been a demonstration of
anything but that. MAINTAINERS entry was a bit confusing since defacto
drm has been maintaining it for years.

It was marked as 'Orphaned'. Anyone is free to send a Patch/PR to take
over maintainership. If you have strong opinions about that code (And you
obviously have reading your mail, set it to 'maintained' and care about
it. Everything else is just wrong in my opinion.

No, it's not wrong. Helge takes fbdev over the weekend, without noteworthy experience, and ignores advice from the people that have kept it alive over the past years. This isn't going to work in the long term.

Best regards
Thomas


/Sven

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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