On Thu, Aug 13, 2015 at 09:35:21AM +0530, Sivakumar Thulasimani wrote: > > > On 8/12/2015 6:26 PM, Daniel Vetter wrote: > > On Mon, Aug 10, 2015 at 05:51:48PM +0530, Sivakumar Thulasimani wrote: > >> > >> On 8/10/2015 5:44 PM, Jani Nikula wrote: > >>> On Mon, 10 Aug 2015, Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx> wrote: > >>>> On 8/10/2015 5:07 PM, Jani Nikula wrote: > >>>>> On Mon, 10 Aug 2015, Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx> wrote: > >>>>>> Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx> > >>>>>> > >>>>>> On 8/10/2015 10:35 AM, Sonika Jindal wrote: > >>>>>>> With HPD support added for all ports including PORT_A, setting hpd_pin will > >>>>>>> result in enabling of hpd to edp as well. There is no need to enable HPD on > >>>>>>> PORT_A hence this patch removes hpd_pin update for PORT_A, where edp will > >>>>>>> be connected. it can be added back when required > >>>>> What? You can't just go ahead and remove HPD from eDP sinks. > >>>>> > >>>>> BR, > >>>>> Jani. > >>>> Nope, we are not removing HPD for edp sinks, it was never there in the > >>>> first place. It was > >>>> enabled for CHV (even there by mistake since PORT B/C was both DP and > >>>> eDP) but it was > >>>> never there for any other plaforms nor is it used for any purpose (PSR > >>>> must use it, but i > >>>> dont see code for it as well). > >>> Are you saying there's no HPD enabled in our *hardware* for eDP? Or > >>> driver? > >>> > >>> My point is, is this patch making it harder to enable eDP hpd handling > >>> (e.g. for PSR or DP link re-training) in the future? We currently take > >>> it into account in a few places, and if we start removing that, it will > >>> be a loss of effort to first remove and then add it back. > >>> > >>> BR, > >>> Jani. > >> i was referring to our driver only. > >> > >> Our VLV/CHV code already receives hpd for every pps on and off which is > >> later ignored. if we dont disable HPD on eDPs this behavior will be extended > >> for all platforms which i feel is too costly to keep enabled when there is > >> no > >> purpose for it right now. > > don't optimize code because you "feel it's costly", only do it when you > > have hard numbers. One interrupt per pps on or off transition won't be > > measurable at all. > > -Daniel > let me rephrase my concern then :) > a) HPD was never enabled before this patch for edp It was for port!=A, which means all VLV/CHV + some other machines with eDP on port D. > b) this patch series will enable hpd for edp > so why should we allow hpd for edp when no one is using it and will > cause problems > unless ignored explicitly ? It's not clear it would cause problems. My ILK still seems happy now that I enabled port A HPD on it [1]. As are the VLV/CHV machines. On BSW we had problems but that turned out to be misconfigured pullups on the HPD pins. Before that got fixed there was a lot of noise on the line whenever the panel was off, and that spurred me to write the patch series to keep the HPD disabled while the port is disabled [2]. [1] http://lists.freedesktop.org/archives/intel-gfx/2015-August/073559.html [2] http://lists.freedesktop.org/archives/intel-gfx/2015-January/058173.html -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
