Re: [PATCH] drm/i195/bxt: Add A1 stepping for Broxton

[Nick Hoath <nicholas.hoath@intel.com>]

On 05/05/2015 17:18, Deak, Imre wrote:
> On ti, 2015-05-05 at 15:20 +0100, Nick Hoath wrote:
>> On 29/04/2015 15:35, Deak, Imre wrote:
>>> On pe, 2015-03-20 at 09:29 +0000, Nick Hoath wrote:
>>>> This stepping isn't listed separately in the specs, so needs confirmation.
>>>>
>>>> Signed-off-by: Nick Hoath <nicholas.hoath@intel.com>
>>>> ---
>>>>    drivers/gpu/drm/i915/i915_drv.h | 1 +
>>>>    1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>>>> index eec271a..68fb41a 100644
>>>> --- a/drivers/gpu/drm/i915/i915_drv.h
>>>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>>>> @@ -2329,6 +2329,7 @@ struct drm_i915_cmd_table {
>>>>    #define SKL_REVID_E0		(0x4)
>>>>
>>>>    #define BXT_REVID_A0		(0x0)
>>>> +#define BXT_REVID_A1		(0x1)
>>>
>>> The above mapping is for the SOC RevID, but I think for all our purposes
>>> (WAs) we should check the GT/Display RevID. The A1 GT/Display RevID
>>> doesn't seem to exist, only A0 is defined with all of 0,1,2 RevIDs
>>> mapping to A0.
>>
>> We use the GT Device2 Revision ID for these comparisons, which does
>> change on each SoC revision. This may map to A0 GT stepping for all the
>> Ax SoCs, according to the specs. However, as this is a naming convention
>> that doesn't affect the code, I suggest we stick to what I have in this
>> patch even if it doesn't 100% reflect what's in the specs.
>
> Not sure about this, as I understand all the workarounds are marked with
> the GT stepping not the SOC stepping, even though the latter is more
> fine-grained. Is there any workarounds for A1? If not I'd suggest adding
> this macro only when we need it.


Agreed, consider this patch currently N/A.

>
> --Imre
>
>>>>    #define BXT_REVID_B0		(0x3)
>>>>    #define BXT_REVID_C0		(0x6)
>>>>
>>>
>>>
>>
>
>

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