Re: WAs in init_clock_gating?

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Jul 24, 2014 at 11:43:11AM +0100, Siluvery, Arun wrote:
> On 07/07/2014 22:24, Daniel Vetter wrote:
> >On Mon, Jul 7, 2014 at 11:16 PM, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> >>I don't think it's unreasonable to use a macro that checks a global
> >>list for whether to apply a given WA.  They'll be scattered all over,
> >>but at least it'll be easy to see:
> >>   1) whether we implement a given workaround
> >>and
> >>   2) which platforms & steppings it applies to based on the table.
> >
> >Oh, I agree it's not unreasonable. But I'm kinda begging for the
> >simple solution since months (years?) and haven't gotten it, while
> >still getting a steady stream of bug reports and issues. So I've
> >readjusted my expectations ;-)
> >
> >If someone delivers the real deal I'll certainly won't reject it.
> >-Daniel
> >
> 
> I am moving bdw workarounds from clock_gating fn to render ring init fn and
> testing this before and after gpu reset.

Testing = with an igt? Because I'll ask for this ;-)

> One of the workaround is to disable STC optimization, reg CACHE_MODE_1 bit6
> set to 1. I observed that some times after boot this gets reset to 0
> (default value) even after applying workarounds; other than workarounds no
> one else seems to write to this function.
> Any ideas about this behaviour?

gpu init tends to do this, since clock_gating is run before that.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch