Hi, On Thu, 20 Apr 2017 09:27:34 +0300 Tomi Valkeinen <tomi.valkeinen@xxxxxx> 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@xxxxxxxxxxxx> Regards, Andreas
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