[Intel-gfx] [PATCH v2] drm/i915/gen9: implement WaConextSwitchWithConcurrentTLBInvalidate

[Arun Siluvery]

On 10/06/2016 12:16, Gore, Tim wrote:
>
>
> Tim Gore
> Intel Corporation (UK) Ltd. - Co. Reg. #1134945 - Pipers Way, Swindon SN3 1RJ
>
>
>> -----Original Message-----
>> From: Arun Siluvery [mailto:arun.siluvery at linux.intel.com]
>> Sent: Friday, June 10, 2016 7:30 AM
>> To: Gore, Tim; intel-gfx at lists.freedesktop.org
>> Subject: Re: [PATCH v2] drm/i915/gen9: implement
>> WaConextSwitchWithConcurrentTLBInvalidate
>>
>> On 09/06/2016 20:19, tim.gore at intel.com wrote:
>>> From: Tim Gore <tim.gore at intel.com>
>>>
>>> This patch enables a workaround for a mid thread preemption issue
>>> where a hardware timing problem can prevent the context restore from
>>> happening, leading to a hang.
>>>
>>> v2: move to gen9_init_workarounds (Arun)
>>>
>>> Signed-off-by: Tim Gore <tim.gore at intel.com>
>>> ---
>>>    drivers/gpu/drm/i915/i915_reg.h         | 4 ++++
>>>    drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++
>>>    2 files changed, 7 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_reg.h
>>> b/drivers/gpu/drm/i915/i915_reg.h index 81d1896..2a6fc62 100644
>>> --- a/drivers/gpu/drm/i915/i915_reg.h
>>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>>> @@ -1810,6 +1810,10 @@ enum skl_disp_power_wells {
>>>    #define   GEN9_IZ_HASHING_MASK(slice)			(0x3 <<
>> ((slice) * 2))
>>>    #define   GEN9_IZ_HASHING(slice, val)			((val) <<
>> ((slice) * 2))
>>>
>>> +/* chicken reg for WaConextSwitchWithConcurrentTLBInvalidate */
>>> +#define GEN9_CSFE_CHICKEN1_RCS _MMIO(0x20D4)
>>> +#define   GEN9_PREEMPT_GPGPU_SYNC_SWITCH_DISABLE (1 << 2)
>>> +
>>>    /* WaClearTdlStateAckDirtyBits */
>>>    #define GEN8_STATE_ACK		_MMIO(0x20F0)
>>>    #define GEN9_STATE_ACK_SLICE1	_MMIO(0x20F8)
>>> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c
>>> b/drivers/gpu/drm/i915/intel_ringbuffer.c
>>> index cf8d0bf..7c756ac 100644
>>> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
>>> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
>>> @@ -1022,6 +1022,9 @@ static int gen9_init_workarounds(struct
>> intel_engine_cs *engine)
>>>    	if (ret)
>>>    		return ret;
>>>
>>> +	/* WaConextSwitchWithConcurrentTLBInvalidate:skl,bxt,kbl */
>>> +	I915_WRITE(GEN9_CSFE_CHICKEN1_RCS,
>>>
>> +_MASKED_BIT_ENABLE(GEN9_PREEMPT_GPGPU_SYNC_SWITCH_DISABLE)
>> );
>>> +
>> WA_SET_BIT_MASKED(GEN9_CSFE_CHICKEN1_RCS,
>> GEN9_PREEMPT_GPGPU_SYNC_SWITCH_DISABLE);
>>
>> Please correct the spelling.
>> We should try to keep WA regs in some order although it is not true for some
>> of the existing ones but we should try to follow this rule for the new ones;
>> HW whitelist registers are normally kept at the end.
>> I think the correct place for this one is at the beginning of this function to
>> maintain increasing order.
>>
>> regards
>> Arun
>>
>>
> Which spelling do you want corrected?

WaConextSwitchWithConcurrentTLBInvalidate - two occurrences.

regards
Arun

>
>    Tim
>>>    	return 0;
>>>    }
>>>
>>>
>
>