[PATCH 1/3] drm/omap: work-around for omap3 display enable

[Aaro Koskinen]

Hi,

On Wed, Aug 23, 2017 at 12:33:08PM +0300, Tomi Valkeinen wrote:
> On 13/06/17 12:02, Tomi Valkeinen wrote:
> > Seems that on omap3 enabling a crtc without any planes causes a sync
> > lost flood. This only happens on the first enable, and after that it
> > works. This looks like an HW issue.
> > 
> > It's unclear why this is happening or how to fix it, but as a quick
> > work-around, this patch enables i734 errata work-around for omap2 and
> > omap3 too. The errata work-around enables and disables the LCD output
> > with a plane once when waking up the DSS IP, and it seems to resolve the
> > omap3 problem too. It is unclear if omap2 has the same issue, but it
> > probably has and the WA should have no side effects so it should be safe
> > to enable on omap2 too.
> 
> I was again debugging and testing this problem, and I don't think this patch
> works very well. I'm getting endless sync losts again.
> 
> Here's another try, this time changing how the omapdrm commits the new setup.
> At least for me this seems to work better.
>
> From fc5cc9678e130196012c17b37e555d53d3d3476b Mon Sep 17 00:00:00 2001
> From: Tomi Valkeinen <tomi.valkeinen at ti.com>
> Date: Wed, 23 Aug 2017 12:19:02 +0300
> Subject: [PATCHv2] drm/omap: work-around for omap3 display enable

Thanks! I was finally able to test this (with v4.13). Multiple boots
and now the display is always working fine.

A.