[Intel-gfx] [PATCH v4 1/1] drm/i915/gt: Initialize reserved and unspecified MOCS indices

[Lucas De Marchi]

On Fri, Jul 31, 2020 at 12:23:57AM -0700, Siddiqui, Ayaz A wrote:
>
>
>> -----Original Message-----
>> From: Siddiqui, Ayaz A <ayaz.siddiqui at intel.com>
>> Sent: Wednesday, July 29, 2020 3:56 PM
>> To: intel-gfx at lists.freedesktop.org
>> Cc: Siddiqui, Ayaz A <ayaz.siddiqui at intel.com>; Chris Wilson <chris at chris-
>> wilson.co.uk>; De Marchi, Lucas <lucas.demarchi at intel.com>; Lis, Tomasz
>> <tomasz.lis at intel.com>; Roper, Matthew D <matthew.d.roper at intel.com>;
>> Joonas Lahtinen <joonas.lahtinen at linux.intel.com>; Francisco Jerez
>> <currojerez at riseup.net>; Mathew, Alwin <alwin.mathew at intel.com>; Mcguire,
>> Russell W <russell.w.mcguire at intel.com>; Spruit, Neil R
>> <neil.r.spruit at intel.com>; Zhou, Cheng <cheng.zhou at intel.com>; Benemelis,
>> Mike G <mike.g.benemelis at intel.com>
>> Subject: [PATCH v4 1/1] drm/i915/gt: Initialize reserved and unspecified MOCS
>> indices
>>
>> In order to avoid functional breakage of mis-programmed applications that have
>> grown to depend on unused MOCS entries, we are programming those entries to
>> be equal to fully cached ("L3 + LLC") entry.
>>
>> These reserved and unspecified entries should not be used as they may be
>> changed to less performant variants with better coherency in the future if more
>> entries are needed.
>>
>> V2: As suggested by Lucas De Marchi to utilise __init_mocs_table for
>> programming default value, setting I915_MOCS_PTE index of tgl_mocs_table
>> with desired value.
>>
>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>> Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>> Cc: Tomasz Lis <tomasz.lis at intel.com>
>> Cc: Matt Roper <matthew.d.roper at intel.com>
>> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
>> Cc: Francisco Jerez <currojerez at riseup.net>
>> Cc: Mathew Alwin <alwin.mathew at intel.com>
>> Cc: Mcguire Russell W <russell.w.mcguire at intel.com>
>> Cc: Spruit Neil R <neil.r.spruit at intel.com>
>> Cc: Zhou Cheng <cheng.zhou at intel.com>
>> Cc: Benemelis Mike G <mike.g.benemelis at intel.com>
>>
>> Signed-off-by: Ayaz A Siddiqui <ayaz.siddiqui at intel.com>
>> Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>
>> ---
>>  drivers/gpu/drm/i915/gt/intel_mocs.c | 15 +++++++++++----
>>  1 file changed, 11 insertions(+), 4 deletions(-)
>>
>
>I'm getting a false failure with this patch , which I tested locally and its passing
>with this patch. I think that this failure is blocking merge of this patch.
>Can Someone please let me know how to proceed in this case for merging?

If it's a false failure, you can go ahead and merge it. Better to reply
to the CI email how is it unrelated.

If you are not sure, you can re-trigger CI by going to the patchwork
page and asking it to test revision 5 again:
https://patchwork.freedesktop.org/series/78012/

Lucas De Marchi

>
>Regards
>-Ayaz
>
>> diff --git a/drivers/gpu/drm/i915/gt/intel_mocs.c
>> b/drivers/gpu/drm/i915/gt/intel_mocs.c
>> index 632e08a4592b..f5dde723f612 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_mocs.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_mocs.c
>> @@ -234,11 +234,17 @@ static const struct drm_i915_mocs_entry
>> broxton_mocs_table[] = {
>>  		   L3_1_UC)
>>
>>  static const struct drm_i915_mocs_entry tgl_mocs_table[] = {
>> -	/* Base - Error (Reserved for Non-Use) */
>> -	MOCS_ENTRY(0, 0x0, 0x0),
>> -	/* Base - Reserved */
>> -	MOCS_ENTRY(1, 0x0, 0x0),
>>
>> +	/* NOTE:
>> +	 * Reserved and unspecified MOCS indices have been set to (L3 + LCC).
>> +	 * These reserved entries should never be used, they may be changed
>> +	 * to low performant variants with better coherency in the future if
>> +	 * more entries are needed. We are programming index
>> I915_MOCS_PTE(1)
>> +	 * only, __init_mocs_table() take care to program unused index with
>> +	 * this entry.
>> +	 */
>> +	MOCS_ENTRY(1, LE_3_WB | LE_TC_1_LLC | LE_LRUM(3),
>> +		   L3_3_WB),
>>  	GEN11_MOCS_ENTRIES,
>>
>>  	/* Implicitly enable L1 - HDC:L1 + L3 + LLC */ @@ -265,6 +271,7 @@
>> static const struct drm_i915_mocs_entry tgl_mocs_table[] = {
>>  	MOCS_ENTRY(61,
>>  		   LE_1_UC | LE_TC_1_LLC,
>>  		   L3_3_WB),
>> +
>>  };
>>
>>  static const struct drm_i915_mocs_entry icl_mocs_table[] = {
>> --
>> 2.26.2
>