[PATCH 3/3] drm/xe/xelp: Add Wa_18022495364

[Tvrtko Ursulin]

On 16/05/2025 20:06, Matt Roper wrote:
> On Fri, May 16, 2025 at 08:44:12AM +0100, Tvrtko Ursulin wrote:
>> Add Wa_18022495364 as a context indirect workaround.
>>
>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
>> ---
>>   drivers/gpu/drm/xe/regs/xe_engine_regs.h |  3 +++
>>   drivers/gpu/drm/xe/xe_lrc.c              | 12 ++++++++++++
>>   drivers/gpu/drm/xe/xe_wa_oob.rules       |  1 +
>>   3 files changed, 16 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/regs/xe_engine_regs.h b/drivers/gpu/drm/xe/regs/xe_engine_regs.h
>> index d1d2592e010d..94d778d5425d 100644
>> --- a/drivers/gpu/drm/xe/regs/xe_engine_regs.h
>> +++ b/drivers/gpu/drm/xe/regs/xe_engine_regs.h
>> @@ -112,6 +112,9 @@
>>   #define   PPHWSP_CSB_AND_TIMESTAMP_REPORT_DIS	REG_BIT(14)
>>   #define   CS_PRIORITY_MEM_READ			REG_BIT(7)
>>   
>> +#define CS_DEBUG_MODE2(base)			XE_REG((base) + 0xd8, XE_REG_OPTION_MASKED)
>> +#define   INSTRUCTION_STATE_CACHE_INVALIDATE	REG_BIT(6)
>> +
>>   #define FF_SLICE_CS_CHICKEN1(base)		XE_REG((base) + 0xe0, XE_REG_OPTION_MASKED)
>>   #define   FFSC_PERCTX_PREEMPT_CTRL		REG_BIT(14)
>>   
>> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
>> index 6022068ce6b6..9a07fc6d78ab 100644
>> --- a/drivers/gpu/drm/xe/xe_lrc.c
>> +++ b/drivers/gpu/drm/xe/xe_lrc.c
>> @@ -1028,6 +1028,15 @@ xelp_emit_cmd_buf_wa(struct xe_lrc *lrc, u32 *cmd)
>>   	return cmd;
>>   }
>>   
>> +static u32 *xelp_invalidate_state_cache(u32 *cmd)
>> +{
>> +	*cmd++ = MI_LOAD_REGISTER_IMM | MI_LRI_NUM_REGS(1);
>> +	*cmd++ = CS_DEBUG_MODE1(0).addr;
>> +	*cmd++ = _MASKED_BIT_ENABLE(INSTRUCTION_STATE_CACHE_INVALIDATE);
>> +
>> +	return cmd;
>> +}
>> +
>>   static u32 *
>>   xelp_setup_indirect_ctx_rcs(struct xe_lrc *lrc, struct xe_hw_engine *hwe,
>>   			    u32 *cmd)
>> @@ -1037,6 +1046,9 @@ xelp_setup_indirect_ctx_rcs(struct xe_lrc *lrc, struct xe_hw_engine *hwe,
>>   	cmd = xelp_emit_cmd_buf_wa(lrc, cmd);
>>   	cmd = xelp_emit_restore_scratch(lrc, cmd);
>>   
>> +	if (XE_WA(lrc->gt, 18022495364))
>> +		cmd = xelp_invalidate_state_cache(cmd);
> 
> This is another one where the official workaround description asks us to
> use the per-context workaround bb rather than the indirect context
> workaround bb.  This register is already part of the LRC, so which batch
> buffer gets used determines whether this extra write will happen before
> or after the standard write that would have been part of the LRC
> restore; I'm not sure if that matters or not from a functional
> perspective.

Interesting. I will change it over and try to remember to raise an i915 
issue to fix it up there too.

Also looping in Lionel in case he could have a feeling if some Mesa bugs 
could be cause by 18022495364 being potentially not correctly 
implemented. I *think* I saw this WA mentioned in one recent issue 
discussing push constants or something like that.

Regards,

Tvrtko

>> +
>>   	return cmd;
>>   }
>>   
>> diff --git a/drivers/gpu/drm/xe/xe_wa_oob.rules b/drivers/gpu/drm/xe/xe_wa_oob.rules
>> index 9efc5accd43d..a32f5ee9e917 100644
>> --- a/drivers/gpu/drm/xe/xe_wa_oob.rules
>> +++ b/drivers/gpu/drm/xe/xe_wa_oob.rules
>> @@ -1,4 +1,5 @@
>>   1607983814	GRAPHICS_VERSION_RANGE(1200, 1210)
>> +18022495364	GRAPHICS_VERSION_RANGE(1200, 1210)
>>   22012773006	GRAPHICS_VERSION_RANGE(1200, 1250)
>>   14014475959	GRAPHICS_VERSION_RANGE(1270, 1271), GRAPHICS_STEP(A0, B0)
>>   		PLATFORM(DG2)
>> -- 
>> 2.48.0
>>
>