Re: [PATCH] drm/i915/guc: Removed unused GuC parameters.

["Piorkowski, Piotr" <piotr.piorkowski@intel.com>]

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On Fri, 2018-03-02 at 12:53 +0530, Sagar Arun Kamble wrote:
> 
> On 3/2/2018 12:44 AM, John Spotswood wrote:
> > On Thu, 2018-03-01 at 17:35 +0530, Sagar Arun Kamble wrote:
> > > On 3/1/2018 1:32 PM, Chris Wilson wrote:
> > > > Quoting Michel Thierry (2018-02-28 22:07:51)
> > > > > On 28/02/18 12:26, Michel Thierry wrote:
> > > > > > On 28/02/18 10:42, Piotr Piórkowski wrote:
> > > > > > > In the i915 driver, there is a function,
> > > > > > > intel_guc_init_params(),
> > > > > > > which initializes the GuC parameter block which is passed
> > > > > > > into
> > > > > > > the GuC. There is parameter GUC_CTL_DEVICE_INFO with
> > > > > > > values
> > > > > > > GfxGtType and GfxCoreFamily unused by GuC.
> > > > > > > 
> > > > > > > This patch remove GUC_CTL_DEVICE_INFO with GfxGtType and
> > > > > > > GfxCoreFamily parameters and also unnecessary functions
> > > > > > > get_gt_type() and get_core_family().
> > > > > > > 
> > > > > > 
> > > > > > Hi,
> > > > > > 
> > > > > > Looking at the fw code, you're partially right, GfxGtType
> > > > > > is
> > > > > > ignored...
> > > > > > but GfxCoreFamily isn't.
> > > > > > 
> > > > > 
> > > > > Unless whoever wrote the fw was smart enough to forget to
> > > > > call
> > > > > the
> > > > > function that is reading GfxCoreFamily... I didn't count on
> > > > > that.
> > > > 
> > > > Is the intention to use GfxCoreFamily documented, i.e. are they
> > > > expecting it part of the interface and may re-instantiate the
> > > > check
> > > > "because it was always supposed to exist" in some future
> > > > version?
> > > 
> > > Usage of GfxCoreFamily is only in SLPC and for platform specific
> > > initialization and might be removed in future interfaces.
> > > If needed, we can add as part of SLPC patches.
> > 
> > Michel and I have traced through the FW code, and both parameters
> > are
> > unused.  GfxCoreFamily does appear to be set in the FW, and it gets
> > passed into SLPC, but then it never gets used.
> 
> Hi John,
> 
> It is needed for SLPC initialization. Verified on v9 GuC firmware
> that 
> SLPC GTPERF gets disabled if i915 does not send this param.
> We can add this param as part of SLPC patches for GuC versions which 
> need them.

Ok, so I think that we should remove this param from i915, and than if 
it is needed, we can add this param as part of SLPC patches, as Sagar
said.

-Piotr 
> 
> Thanks
> Sagar
> >    I have confirmed with
> > FW developers that these parameters have been removed for future
> > gens.
> > > > -Chris
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx@lists.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> 

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