[Intel-gfx] debugging Haswell eDP black screen after S3

Daniel Vetter daniel at ffwll.ch
Tue May 21 16:02:08 CEST 2013

On Tue, May 21, 2013 at 3:44 PM, Ben Guthro <ben at guthro.net> wrote:
>> This will break kms since now you have the vbios and the linux kms driver
>> fighting over the same piece of hw. Does
>> xset dpms force off
>> xset dpms force on
>> cause similar issues?
> No, these work as expected (on 3.8)
> I didn't realize that these broke with KMS. I'll stick with the S3 reproduction.

Ok, so things are at least not terribly broken.

>> If not please make sure that vbetool isn't badly interfering with the
>> kernel modeset driver on suspend/resume. At least looking at your dmesg
>> and reg dumps vbe wreaking havoc with the kms driver seems like a rather
>> likely scenario. Also, can you please test latest 3.10-rc kernels?
> 3.10-rc2 doesn't seem to work at all - it boots to a black screen every time.

That otoh is ugly. Could be that though that this is the same (or a
similar bug) to your resume issue - in the last few kernel releases
we've tried very hard to unify the code between initial driver load at
boot-up and resume.

So can you please try to bisect where the boot-up regression has been
introduced between 3.8 and 3.10-rc2?

Thanks, Daniel
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

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