Re: [PATCH 1/1] drm/i915/tgl: Implement Wa_1604555607

From: Lucas De Marchi <lucas.de.marchi@gmail.com>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>,
	intel-gfx <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH 1/1] drm/i915/tgl: Implement Wa_1604555607
Date: Tue, 26 Nov 2019 01:38:20 -0800	[thread overview]
Message-ID: <CAKi4VAKNfh5uriVmi6H7wev3XhwMrGrArsaqrGWHJ=qa=vZuzw@mail.gmail.com> (raw)
In-Reply-To: <157441498323.2524.12613965179682887118@skylake-alporthouse-com>

On Fri, Nov 22, 2019 at 1:30 AM Chris Wilson <chris@chris-wilson.co.uk> wrote:
>
> Quoting Tvrtko Ursulin (2019-11-22 09:21:45)
> >
> > On 22/11/2019 04:02, Ramalingam C wrote:
> > > @@ -568,9 +581,22 @@ static void icl_ctx_workarounds_init(struct intel_engine_cs *engine,
> > >   static void tgl_ctx_workarounds_init(struct intel_engine_cs *engine,
> > >                                    struct i915_wa_list *wal)
> > >   {
> > > +     u32 val;
> > > +
> > >       /* Wa_1409142259:tgl */
> > >       WA_SET_BIT_MASKED(GEN11_COMMON_SLICE_CHICKEN3,
> > >                         GEN12_DISABLE_CPS_AWARE_COLOR_PIPE);
> > > +
> > > +     /* Wa_1604555607:tgl */
> > > +     val = intel_uncore_read(engine->uncore, FF_MODE2);
> > > +     val &= ~FF_MODE2_TDS_TIMER_MASK;
> > > +     val |= FF_MODE2_TDS_TIMER_128;
> > > +     /*
> > > +      * FIXME: FF_MODE2 register is not readable till TGL B0. We can
> > > +      * enable verification of WA from the later steppings, which enables
> > > +      * the read of FF_MODE2.
> > > +      */
> > > +     __wa_write_masked_or(wal, FF_MODE2, FF_MODE2_TDS_TIMER_MASK, val, 0);
> >
> > If I was a betting man I'd bet no one will ever remember to add the
> > verification back. So I have to say I disagree with Lucas on this point.
> > Someone do a casting vote please. :)
>
> I would go with IS_TGL_REVID(A0, A0) as we expect it to be picked up by

then it is broken from start? In A2 it's not fixed yet.... not sure if
CI has A2.
But we should add at least A2 and A3 and make it pass on these.

Lucas De Marchi

> the selftests if we have a new stepping that is unfixed -- and a blip in
> CI is a much clearer reminder to come back and revisit this code. We
> should be able to go "oops, live_workarounds is red, failing on ctx:0xf00"
> and from there find this fixme. And so update for a new stepping in the
> course of a day (because that's how long it takes for CI to approve a
> patch).
> -Chris
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-- 
Lucas De Marchi
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