[PATCH] drm/i915/rc6: Disable RPG during workload execution

[Gupta, Anshuman]

> -----Original Message-----
> From: Nilawar, Badal <badal.nilawar at intel.com>
> Sent: Wednesday, October 23, 2024 9:42 PM
> To: Vivi, Rodrigo <rodrigo.vivi at intel.com>
> Cc: Andi Shyti <andi.shyti at linux.intel.com>; intel-gfx at lists.freedesktop.org;
> Gupta, Anshuman <anshuman.gupta at intel.com>;
> chris.p.wilson at linux.intel.com
> Subject: Re: [PATCH] drm/i915/rc6: Disable RPG during workload execution
> 
> 
> 
> On 23-10-2024 21:31, Nilawar, Badal wrote:
> >
> >
> > On 23-10-2024 20:18, Rodrigo Vivi wrote:
> >> On Wed, Oct 23, 2024 at 11:03:57AM +0530, Nilawar, Badal wrote:
> >>>
> >>>
> >>> On 22-10-2024 22:39, Rodrigo Vivi wrote:
> >>>> On Tue, Oct 22, 2024 at 03:28:43PM +0200, Andi Shyti wrote:
> >>>>> Hi Badal,
> >>>>>
> >>>>> On Tue, Oct 22, 2024 at 06:52:26PM +0530, Badal Nilawar wrote:
> >>>>>> Encountering forcewake errors related to render power gating;
> >>>>>
> >>>>> Can you please expand your explanation here?
> >>>>
> >>>> yeap. More explanation please. All platforms? really?
> >>>
> >>> We are seeing Render forcewake timeouts on ADLP, ADLM, ADLN, TWL,
> >>> DG1, rpl.
> >>
> >> Is this a regression? or a new issue?
> >
> > This is old issue, first reported year back.
> >
> >>
> >> Is this happening with Xe on these platforms? or i915 only?
> >
> > i915 only. This is not reported on Xe kmd.
> >
> >>
> >>> Issue disappears after disabling RPG. Instead of fully disabling RPG
> >>> I am disabling it during active submissions i.e. during unpark.
> >>> For MTL and ARL RPG is already disabled permanently.
IMO this patch should be extended for MTL and ARL as well.
Don't disable the RPG completely, only disable it during workload submission.
That should save power on both MTL and ARL platforms, and right thing to do.
And patch should add the Fixes tag accordingly to the commit which disables the RPG on MTL.
@Vivi, Rodrigo what is your opinion on above ? it seems both MTL and ADL issues are same signature.
MTL issue got disappear as RPG is disabled globally but that will burn power.
If window does not have this issue then it is always difficult to get proper SV support.  
But OS like window may not catch these kind of issues as they don't reload the their graphics driver like
Linux reload module multiple times during selftest execution. Even chrome-os does not do that.
Not a real world use case.
Thanks,
Anshuman.
> >>
> >> uhm. Interesting. Why that is disabled on these platforms?
> >
> >  From commit log its temporary wa to avoid fw timeouts.
> >
> > perhaps we should be
> >> doing the same for all GuC enabled platforms?
> >
> > I think so as temporary Wa.
> 
> Correction, DG1 we are not seeing this. I think we can go with platform check.
> 
> Regards,
> Badal