[PATCH] xf86-video-intel: deactivate unused CRTCs

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Monday 26 March 2012 14:22:02 Chris Wilson wrote:
> On Thu, 15 Dec 2011 13:46:28 +0100, Helge Bahmann <helge.bahmann at secunet.com> wrote:
> > Hi everyone,
> >
> > would you mind putting something along the following into
> > xf86-video-intel?
>
> A few months later... I looked at this and concluded that it is just
> working around a kernel bug, which I'm always optimistic will be
> resolved in the next release.
> -Chris

Most likely there is a "bug" in my understandig of how X-Server and drm console layer are supposed 
to cooperate:

- how does the kernel layer reliably distinguish between the states "userspace manages display heads 
vs. "kernel console layer manages display heads" ?
- how does the kernel layer reliably detect the "ground state" from which userspace starts setting 
up things ?
- what assumptions may user-space make on the "left-over" state when it takes over responsibility?

I don't think kernel code currently handles these issues too well, resulting in a number of odd 
corner cases when plugging/unplugging displays at the "right" times (while switched away from X, 
while in suspend-to-ram state, while X server resumes but is slow to re-setup things because it got 
paged out...). My best shot at fixing this was to have X not make too many assumptions on the state 
after taking over, and bring everything into a well-defined state.

Could you perhaps briefly explain how the interaction is supposed to look? I would really like to 
provide a more "correct" fix, but I don't fully grasp the intended model so far.

Best regards
Helge
-- 
Dr.-Ing.
Helge Bahmann
Berater
Gesch?ftsbereich Hochsicherheit
secunet Security Networks AG
Ammonstra?e 74
01067 Dresden, Germany
Fon: +49 201 54 54-3586
Fax: +49 201 54 54-1323
Email: helge.bahmann at secunet.com

Sitz: Kronprinzenstra?e 30, 45128 Essen
Amtsgericht Essen HRB 13615
Vorstand: Dr. Rainer Baumgart, Thomas Koelzer, Thomas Pleines
Aufsichtsratsvorsitzender: Dr. Karsten Ottenberg


[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]
  Powered by Linux