On Wed, Mar 04, 2020 at 04:24:13PM +0000, Tvrtko Ursulin wrote: > > On 04/03/2020 16:02, Rafael Antognolli wrote: > > On Wed, Mar 04, 2020 at 03:31:44PM +0000, Tvrtko Ursulin wrote: > > > From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > > > > > Enable FtrPerCtxtPreemptionGranularityControl bit and select thread- > > > group as the default preemption level. > > > > > > v2: > > > * Remove register whitelisting (Rafael, Tony). > > > > > > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > > Cc: Michał Winiarski <michal.winiarski@xxxxxxxxx> > > > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > > > Cc: piotr.zdunowski@xxxxxxxxx > > > Cc: michal.mrozek@xxxxxxxxx > > > Cc: Tony Ye <tony.ye@xxxxxxxxx> > > > Cc: Rafael Antognolli <rafael.antognolli@xxxxxxxxx> > > > > Thanks for CC'ing me. I also saw a reply from Jason yesterday, but I > > don't see it in the list now (though my mail client a mess lately). > > I saw nothing from Jason, but there was an email from you asking about > interface descriptors and whitelisting which is why I copied you. > > > But he asked whether it's possible for Media and OpenCL drivers to > > also disable mid-thread preemption through the > > INTERFACE_DESCRIPTOR_DATA, instead of from the kernel side, so we could > > try to experiment with it in the future. > > > > Also, do you have an idea of how broken it is? Or is it just not tested > > because no driver is currently implementing it? And do you know if the > > windows 3D drivers implement it at all? I see code in the driver that > > seems to me that it's only disabled in certain cases... > > > > To summarize, I think we should either: > > 1) Disable mid-thread preemption from the kernel and not whitelist > > the register (just like you do in this patch); or > > 2) Not do anything at all from the kernel, and let userspace disable > > it if needed. > > > > I think 2) is better, if it's not an issue to the other userspace > > drivers (OpenCL and Media). > > I know it is somewhat broken like in > https://gitlab.freedesktop.org/drm/intel/issues/1293. > > And I know OpenCL and Media would prefer i915 to handle it, but that's > always the case. :) OpenCL and Media folks are on the thread so can comment > if they are okay with handling this themselves. > > Indeed a blanket ban in i915 means no one can try it out later without > further kernel changes. Well, based on your comment from the previous patch: "General thinking is, since MTP is considered not validated / broken / dangerous, i915 should default it off. But yes, whitelisting or not on top is open." Maybe we should simply ban it and be done. So this patch is: Acked-by: Rafael Antognolli <rafael.antognolli@xxxxxxxxx> > Regards, > > Tvrtko _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
