Re: [PATCH 4/4] drm/i915/tgl: Report valid VDBoxes with SFC capability

[Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>]

On 7/30/19 10:59 PM, Tvrtko Ursulin wrote:
> 
> On 31/07/2019 01:49, Daniele Ceraolo Spurio wrote:
>> From: Michel Thierry <michel.thierry@intel.com>
>>
>> In Gen11, only even numbered "logical" VDBoxes are hooked up to a SFC
>> (Scaler & Format Converter) unit. This is not the case in Tigerlake,
>> where each VDBox can access a SFC.
>>
>> We will use this information to decide when the SFC units need to be 
>> reset
>> and also pass it to the GuC.
>>
>> Bspec: 48077
>> Signed-off-by: Michel Thierry <michel.thierry@intel.com>
>> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
>> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
>> Cc: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
>> ---
>>   drivers/gpu/drm/i915/intel_device_info.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_device_info.c 
>> b/drivers/gpu/drm/i915/intel_device_info.c
>> index f99c9fd497b2..2a39b52c3582 100644
>> --- a/drivers/gpu/drm/i915/intel_device_info.c
>> +++ b/drivers/gpu/drm/i915/intel_device_info.c
>> @@ -1022,8 +1022,9 @@ void intel_device_info_init_mmio(struct 
>> drm_i915_private *dev_priv)
>>           /*
>>            * In Gen11, only even numbered logical VDBOXes are
>>            * hooked up to an SFC (Scaler & Format Converter) unit.
>> +         * In TGL each VDBOX has access to an SFC.
>>            */
>> -        if (logical_vdbox++ % 2 == 0)
>> +        if (IS_TIGERLAKE(dev_priv) || logical_vdbox++ % 2 == 0)
>>               RUNTIME_INFO(dev_priv)->vdbox_sfc_access |= BIT(i);
>>       }
>>       DRM_DEBUG_DRIVER("vdbox enable: %04x, instances: %04lx\n",
>>
> 
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> 
> Only uncertainty is if we want to code the condition as Icelake 
> exception instead for more future proofing. Like if "!IS_ICELAKE ||" 
> instead of "IS_TIGERLAKE ||"?

If I'm understanding the specs correctly then this isn't going to apply 
to all future platform and we'll have some of them that behave like ICL 
instead. Maybe a device flag would work better? HAS_SFC_FOR_EACH_VCS()?

Daniele

> 
> Regards,
> 
> Tvrtko
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