Re: [PATCH] MAINTAINERS: Add Helge as fbdev maintainer

On Mon, Jan 17, 2022 at 2:47 PM Helge Deller [off-list ref] wrote:

On 1/17/22 17:21, Helge Deller wrote:

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On 1/17/22 16:58, Thomas Zimmermann wrote:

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Hi

Am 17.01.22 um 16:42 schrieb Helge Deller:

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c) reintroduce the state where fbcon is fast on fbdev. This is important for non-DRM machines,
    either when run on native hardware or in an emulator.
d) not break DRM development

Especially regarding c) I complained in [1] and got no feedback. I really would like to
understand where the actual problems were and what's necessary to fix them.

Helge

[1] https://lore.kernel.org/r/feea8303-2b83-fc36-972c-4fc8ad723bde@gmx.de (local)

Seems like few people read linux-fbdev these days.
I suggest to partly revert the patch to the point were performance
gets better again.

Yes, *please*!
That would solve my biggest concern.

As far as I can see that's only 2 commits to be reverted:
b3ec8cdf457e - "fbdev: Garbage collect fbdev scrolling acceleration, part 1 (from TODO list)"
39aead8373b3 - "fbcon: Disable accelerated scrolling"for-next-next

I think both were not related to any 0-day bug reports (but again, I might be wrong).

I did some more checking...

Both patches are not related to DRM, since no DRM driver sets the
FBINFO_HWACCEL_COPYAREA or FBINFO_HWACCEL_FILLRECT flags.

These used to be set by, at least, nouveau (which is a drm driver).
And yeah, console responsiveness is _way_ worse without that. People
keep pushing the messaging that it's the same speed to do it as
memcpy, but that's just not the case in my experience, on a pretty
bog-standard x86 desktop. The support got dumped, and it felt pretty
clear from the messaging at the time, "too bad". Would love to see it
come back.

Cheers,

  -ilia