[Letux-kernel] regression: drm/omapdrm: Move commit_modeset_enables() before commit_planes()

[Andreas Kemnade]

Hi,

On Thu, 20 Apr 2017 09:27:34 +0300
Tomi Valkeinen <tomi.valkeinen at ti.com> wrote:

> On 19/04/17 18:49, Jyri Sarha wrote:
> > On 04/19/17 16:35, Tomi Valkeinen wrote:
> >> I was able to reproduce on my very old omap3 beagleboard. Looks very
> >> much like a omap3 DSS HW bug to me. The unfortunate thing is that even
> >> reverting the patch won't remove the issue, if the userspace happens to
> >> configure things in certain order.
> >>
> >> It looks to me that if the DSS output is enabled without an overlay (the
> >> primary plane, normally), DSS gets stuck into a bad state, and only
> >> reboot helps (because we can't reset, there's no omap hwmod reset
> >> framework).
> >>
> >> But there should be nothing wrong with that setup, and if there's first
> >> been a successful display enable, then later we can enable the DSS
> >> without any planes.
> > 
> > If that is the case, then maybe we could just enable errata i734 (the
> > gamma bug) work a round for omap3 too. The work a round makes an
> > artificial minimal display setup with GFX plane for one frame, with
> > outputs masked, so it could be exactly what we need.
> 
> Yep, that did come to my mind and I tested it yesterday. However, I
> failed to realize there's the WA init part, and I only made sure the
> dispc_errata_i734_wa() is called.
> 
> Now that I set the bit in the dispc features, it indeed seems to fix the
> issue.
> 
> Below is a hack patch for people to try out. It's based on today's
> linux-next, but should apply to more or less any semi-recent kernel. If
> it works for others, I'll create a proper patch, which drops the
> has_gamma_i734_bug flag and always does the WA.
> 
Tested on gta04a5 with exactly the same manual module loading script as
with the revert. Same result.

So here is my
Tested-by: Andreas Kemnade <andreas at kemnade.info>


Regards,
Andreas
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