[Intel-gfx] Doing restore by setting modes

[Dave Airlie]

On Sun, May 10, 2009 at 10:15 AM, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> On Sat, 09 May 2009 15:10:00 -0700
> Keith Packard <keithp at keithp.com> wrote:
>
>> I'm having trouble with Display Port suspend/resume -- configuring the
>> output is fairly tricky and depends on doing things in the right order
>> at the right time. At this point, on resume, the display refuses to
>> re-train, so you're left with a black screen. Setting the screen to a
>> different mode and back to the preferred mode fixes it, unlike
>> everything else I've tried (including turning it off and back on).
>>
>> I'm wondering if we shouldn't just bail on much of the suspend/resume
>> code and have resume just re-configure outputs using the existing
>> output configuration code. Seems like that would result in less code
>> and fewer inconsistencies between the resume and normal modeset paths.
>
> Yeah, that's been on the TODO list for awhile now.  Though I think we
> may need to keep the current code for non-KMS configs.
>
> We'll also need to keep around a chunk of register save/restore for the
> global, non-mode setting related state, but that should be fairly small
> compared to all the mode stuff.
>
> The KMS save/restore could probably be generic too; we just need to
> save the current mode_config and re-apply it at resume time.
>

Code should already be there.

radeon works like that, there is a helper fn for forcing the modeset.

Dave.

> --
> Jesse Barnes, Intel Open Source Technology Center
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