Re: [pull] drm-intel-next

Stéphane Marchesin
2013-03-18T19:35:46Z

-lkml

On Sun, Mar 17, 2013 at 12:46 PM, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Fri, Mar 15, 2013 at 3:11 AM, Stéphane Marchesin
> <stephane.marchesin@gmail.com> wrote:
>>> drm/i915: read out the modeset hw state at load and resume time
>> This commit regresses modeset on the samsung series 5 chromebook (it
>> is basically a pineview machine with an lvds panel). I don't seem to
>> be able to set any mode on it any longer.
>
> Does that mean the kernel refuses to set the mode, or that you get a
> black screen?
>

I get a black screen.

> For starters I guess we need:
> - drm.debug=0xe dmesg from just before that commit
> - same for latest 3.9-rc kernels, presuming it's not broken there
>
> Latest upstream has a minor chance to work better I think since we've
> improved the pfit handling in the setup and teardown sequence a bit.
>
> Generally lvds has been hit&miss on way too many machines
> unfortunately with things randomly breaking and getting fixed again
> (e.g. one of Chris' machines works again with the new code ...). And
> the commit above doesn't really change much in the code itself but it
> does change the order (and timing) of the different enable/disable
> codepaths.

So I did look at the thing a bit, and it triggers the workaround
if (INTEL_INFO(dev)->gen < 4 && !intel_check_plane_mapping(crtc)) {
which seems to be part of the problem (but not the whole problem as
removing that gets me a corrupted display, looks like the second pipe
stays enabled then).

Stéphane