Re: [PATCH] drm/i915: Wait old forcewake ack to clear on vlv

From: Daniel Vetter <daniel@ffwll.ch>
To: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: "S, Deepak" <deepak.s@intel.com>, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: Wait old forcewake ack to clear on vlv
Date: Wed, 5 Nov 2014 13:42:02 +0100	[thread overview]
Message-ID: <20141105124202.GK26941@phenom.ffwll.local> (raw)
In-Reply-To: <87k33at0ob.fsf@gaia.fi.intel.com>

On Wed, Nov 05, 2014 at 12:13:40PM +0200, Mika Kuoppala wrote:
> Ville Syrjälä <ville.syrjala@linux.intel.com> writes:
> 
> > On Wed, Nov 05, 2014 at 10:18:46AM +0200, Mika Kuoppala wrote:
> >> Don't rush into getting new fw until the clearing
> >> of old one has been acked.
> >> 
> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85684
> >> Tested-by: lu hua <huax.lu@intel.com>
> >> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
> >
> > This is just a revert of 
> >  commit 5cb13c07dae73380d8b3ddc792740487b8742938
> >  Author: Deepak S <deepak.s@linux.intel.com>
> >  Date:   Thu Sep 18 18:51:50 2014 +0530
> >
> >     drm/i915/vlv: Remove check for Old Ack during forcewake
> >
> > except you left the comment behind.
> 
> I failed at archeology. There is even nice comment from Deepak on
> top I managed to miss.
> 
> But after reading this comment and the workaround description, I
> think that this WaRsDontPollForAckOnClearingFWBits is not valid for
> our use case.
> 
> We use only one bit per engine, so our use case is not multithreaded
> in that sense.

Since this is a regression I prefer we apply the revert and then dig
deeper. Mika, can you pls resend as a proper revert? Except ofc when we
have a solution right now, too.

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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