Re: [Intel-xe] [PATCH 2/6] drm/xe: Use full_gt batchbuffer allocation for media tiles.

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

On 2023-04-03 22:27, Matt Roper wrote:
> On Fri, Mar 31, 2023 at 12:24:15PM +0200, Maarten Lankhorst wrote:
>> This fixes an oops on media tiles, because we don't initialise the
>> bb pool.
>> ---
>>   drivers/gpu/drm/xe/xe_gt.c | 10 +++++++---
>>   1 file changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
>> index bc821f431c45..c7a2e9baabfb 100644
>> --- a/drivers/gpu/drm/xe/xe_gt.c
>> +++ b/drivers/gpu/drm/xe/xe_gt.c
>> @@ -237,6 +237,10 @@ int xe_gt_record_default_lrcs(struct xe_gt *gt)
>>   		struct xe_engine *e, *nop_e;
>>   		struct xe_vm *vm;
>>   		void *default_lrc;
>> +		struct xe_gt *full_gt = gt;
>> +
>> +		if (xe_gt_is_media_type(gt))
>> +			full_gt = xe_find_full_gt(gt);
>>   
>>   		if (gt->default_lrc[hwe->class])
>>   			continue;
>> @@ -262,7 +266,7 @@ int xe_gt_record_default_lrcs(struct xe_gt *gt)
>>   		}
>>   
>>   		/* Prime golden LRC with known good state */
>> -		err = emit_wa_job(gt, e);
>> +		err = emit_wa_job(full_gt, e);
> If we pass the primary GT here, then we'll take the wrong path in
> bb_prefetch().  That doesn't actually matter very much (we'll just
> overestimate the padding needed for media engines, which is safe and
> something we already do for BCS engines), but we should probably just
> drop !xe_gt_is_media_type(gt) condition there as part of this patch
> since it will always be true now.

Yeah makes sense. That check doesn't strictly speaking seem to be 
needed, so I'm fine with dropping it.

We could always request the engine to be specified, but I don't think we 
really use those batchbuffers beyond initialisation outside of 
migration/VM_BIND,

which is done on a BCS engine anyway.

Can I have your r-b with that check removed?

~Maarten