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drm/xe/mocs: Drop unwanted TGL table

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TGL/RKL/ADLS/ADLP are all supposed to use the same MOCS table, with
values defined in the bspec.  Any entries listed in the bspec as
reserved/error/undefined should always be initialized to the most cached
and least coherent setting possible so that any userspace accidentally
referencing those undefined entries will only experience an increase in
coherency if spec updates down the road start defining real values.

The TGL and gen12 table entries defined in the driver today are
identical except that the TGL includes one additional (incorrect)
setting for table index 1.  Furthermore, the TGL-specific initialization
does not define a dedicated value for info->unused_entries_index, so
this incorrect table entry 1 also gets used to populate the MOCS
registers for all reserved/unused table entries.  This incorrect
behavior is a holdover from i915 where the platform was enabled with an
incorrect setting and by the time we noticed, it was too late to fix the
table without breaking ABI compatibility (and on TGL we did indeed have
some buggy userspace that was referencing the 'reserved' entry 1).
Since the Xe driver starts fresh with a clean slate on ABI, there's no
need to repeat the mistakes of i915 here.

v2:
 - Reword/clarify commit message.  (Lucas)

Bspec: 45101
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This commit is contained in:
Matt Roper 2023-02-23 10:57:34 -08:00 committed by Rodrigo Vivi
parent 8cb49012ac
commit 7bc08d2f49
1 changed files with 0 additions and 46 deletions
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46
drivers/gpu/drm/xe/xe_mocs.c
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@ -247,47 +247,6 @@ struct xe_mocs_info {
LE_3_WB | LE_TC_1_LLC | LE_LRUM(3), \
L3_1_UC)
static const struct xe_mocs_entry tgl_mocs_desc[] = {
/*
* 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 XE_MOCS_PTE(1)
* only, __init_mocs_table() take care to program unused index with
* this entry.
*/
MOCS_ENTRY(XE_MOCS_PTE,
LE_0_PAGETABLE | LE_TC_0_PAGETABLE,
L3_1_UC),
GEN11_MOCS_ENTRIES,
/* Implicitly enable L1 - HDC:L1 + L3 + LLC */
MOCS_ENTRY(48,
LE_3_WB | LE_TC_1_LLC | LE_LRUM(3),
L3_3_WB),
/* Implicitly enable L1 - HDC:L1 + L3 */
MOCS_ENTRY(49,
LE_1_UC | LE_TC_1_LLC,
L3_3_WB),
/* Implicitly enable L1 - HDC:L1 + LLC */
MOCS_ENTRY(50,
LE_3_WB | LE_TC_1_LLC | LE_LRUM(3),
L3_1_UC),
/* Implicitly enable L1 - HDC:L1 */
MOCS_ENTRY(51,
LE_1_UC | LE_TC_1_LLC,
L3_1_UC),
/* HW Special Case (CCS) */
MOCS_ENTRY(60,
LE_3_WB | LE_TC_1_LLC | LE_LRUM(3),
L3_1_UC),
/* HW Special Case (Displayable) */
MOCS_ENTRY(61,
LE_1_UC | LE_TC_1_LLC,
L3_3_WB),
};
static const struct xe_mocs_entry dg1_mocs_desc[] = {
/* UC */
MOCS_ENTRY(1, 0, L3_1_UC),
@ -422,11 +381,6 @@ static unsigned int get_mocs_settings(struct xe_device *xe,
info->unused_entries_index = 5;
break;
case XE_TIGERLAKE:
info->size = ARRAY_SIZE(tgl_mocs_desc);
info->table = tgl_mocs_desc;
info->n_entries = GEN9_NUM_MOCS_ENTRIES;
info->uc_index = 3;
break;
case XE_ALDERLAKE_S:
case XE_ALDERLAKE_P:
info->size = ARRAY_SIZE(gen12_mocs_desc);