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 <ch...@chris-wilson.co.uk> Cc: Lucas De Marchi <lucas.demar...@intel.com> Cc: Tomasz Lis <tomasz....@intel.com> Cc: Matt Roper <matthew.d.ro...@intel.com> Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com> Cc: Francisco Jerez <curroje...@riseup.net> Cc: Mathew Alwin <alwin.mat...@intel.com> Cc: Mcguire Russell W <russell.w.mcgu...@intel.com> Cc: Spruit Neil R <neil.r.spr...@intel.com> Cc: Zhou Cheng <cheng.z...@intel.com> Cc: Benemelis Mike G <mike.g.beneme...@intel.com> Signed-off-by: Ayaz A Siddiqui <ayaz.siddi...@intel.com> --- drivers/gpu/drm/i915/gt/intel_mocs.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_mocs.c b/drivers/gpu/drm/i915/gt/intel_mocs.c index 632e08a4592b2..c32f90bd56693 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 entry should never be used, they may be chanaged + * 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 prgramm unseud 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 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx