Wa_1608008084 is an additional WA that applies to writes on FF_MODE2
register. We can't read it back either from CPU or GPU. Since the other
bits should be 0, recommendation to handle Wa_1604555607 is to actually
just write the timer value.
Do a write only and don't try to read it, neither before or after
the WA is applied.
Fixes: ff690b2111ba ("drm/i915/tgl: Implement Wa_1604555607")
Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_workarounds.c | 22 ++++++++++-----------
1 file changed, 10 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
index 887e0dc701f7..0d76e1d6ec87 100644
--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
@@ -580,24 +580,22 @@ static void icl_ctx_workarounds_init(struct intel_engine_cs *engine,
static void tgl_ctx_workarounds_init(struct intel_engine_cs *engine,
struct i915_wa_list *wal)
{
- u32 val;
-
/* Wa_1409142259:tgl */
WA_SET_BIT_MASKED(GEN11_COMMON_SLICE_CHICKEN3,
GEN12_DISABLE_CPS_AWARE_COLOR_PIPE);
- /* Wa_1604555607:tgl */
- val = intel_uncore_read(engine->uncore, FF_MODE2);
- val &= ~FF_MODE2_TDS_TIMER_MASK;
- val |= FF_MODE2_TDS_TIMER_128;
/*
- * FIXME: FF_MODE2 register is not readable till TGL B0. We can
- * enable verification of WA from the later steppings, which enables
- * the read of FF_MODE2.
+ * Wa_1604555607:gen12
+ * FF_MODE2 register is not readable till TGL B0, either by CPU or GPU.
+ *
+ * Wa_1608008084:gen12
+ * FF_MODE2 register will return the wrong value when read. The default
+ * value for this register is zero for all fields and there are no bit
+ * masks. So instead of doing a RMW we should just write the TDS timer
+ * value for Wa_1604555607.
*/
- wa_add(wal, FF_MODE2, FF_MODE2_TDS_TIMER_MASK, val,
- IS_TGL_REVID(engine->i915, TGL_REVID_A0, TGL_REVID_A0) ? 0 :
- FF_MODE2_TDS_TIMER_MASK);
+ wa_add(wal, FF_MODE2, FF_MODE2_TDS_TIMER_MASK,
+ FF_MODE2_TDS_TIMER_128, 0);
}
static void
--
2.24.0
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