Re: [igt-dev] [PATCH i-g-t 1/3] lib/i915_blt: Remove src == dst pitch restriction

[Karolina Stolarek <karolina.stolarek@intel.com>]

On 14.12.2022 19:57, Zbigniew Kempczyński wrote:
> On Tue, Dec 13, 2022 at 04:37:26PM +0100, Karolina Stolarek wrote:
>> On 12.12.2022 13:50, Zbigniew Kempczyński wrote:
>>> During debugging phase we established there's not necessary to enforce
>>> same pitch for destination surface in FULL_RESOLVE mode. Relax this
>>> condition allowing caller to pass requirement surface configuration.
>>>
>>> Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski@intel.com>
>>> ---
>>>    lib/i915/i915_blt.c | 8 +++-----
>>>    1 file changed, 3 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/lib/i915/i915_blt.c b/lib/i915/i915_blt.c
>>> index 3776c56c60..42c28623f9 100644
>>> --- a/lib/i915/i915_blt.c
>>> +++ b/lib/i915/i915_blt.c
>>> @@ -317,13 +317,11 @@ static void fill_data(struct gen12_block_copy_data *data,
>>>    	data->dw00.special_mode = __special_mode(blt);
>>>    	data->dw00.length = extended_command ? 20 : 10;
>>> -	if (__special_mode(blt) == SM_FULL_RESOLVE && blt->src.tiling == T_TILE64) {
>>> -		data->dw01.dst_pitch = blt->src.pitch - 1;
>>> +	if (__special_mode(blt) == SM_FULL_RESOLVE)
>>
>> "blt->src.tiling == T_TILE64" part was introduced in commit cdc0258a4672
>> ("lib/i915_blt: Narrow setting same pitch and aux-ccs to Tile64 only").
>> I know it's a bit nit-picky, but could we revert that change (as it looks
>> like it's not necessary), and have a separate commit that removes
>> data->dw01.dst_pitch = blt->src.pitch - 1?
> 
> Two reverts would be necessary: cdc0258a467 and 229bb0accbb7 so single commit
> against three looks better for me. Tiling inplace testing is still in progress.
> If you think better is to revert above and add another commit I'll do it.

To me, some of the 229bb0accbb7 is still here (setting aux_mode), so I'd 
say the revert of it is not necessary. But, yeah, I think it would be 
better to revert cdc0258a467.

> 
>>
>> The question remains -- what actually caused the regression for Tile4 and
>> xmajor? Was it because of the pitch settings? I run the tests a couple of
>> times in the row after applying this patch and everything worked as
>> expected.
> 
> Yes, dst pitch influences on destination surface state. For cascaded
> src->mid->dst mid.pitch may differ from dst.pitch (tileX -> linear blit).
> For inplace there's some side effect which we're debugging now.

OK, so that seems like a root cause. As for inplace, I think it can be 
slightly different, but we can update the function once debugging is 
finished.

All the best,
Karolina

> 
> --
> Zbigniew
> 
>>
>> All the best,
>> Karolina
>>
>>>    		data->dw01.dst_aux_mode = __aux_mode(&blt->src);
>>> -	} else {
>>> -		data->dw01.dst_pitch = blt->dst.pitch - 1;
>>> +	else
>>>    		data->dw01.dst_aux_mode = __aux_mode(&blt->dst);
>>> -	}
>>> +	data->dw01.dst_pitch = blt->dst.pitch - 1;
>>>    	data->dw01.dst_mocs = blt->dst.mocs;
>>>    	data->dw01.dst_compression = blt->dst.compression;