[Intel-gfx] [PATCH] drm/i915/guc: Removed unused GuC parameters.

Sagar Arun Kamble sagar.a.kamble at intel.com
Fri Mar 2 07:23:01 UTC 2018

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.

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


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