From: Ovidiu Bunea <[email protected]>
[Why & How]
DCN42 has 0 bytes allocated for MALL, but this results in a 0 <= 0 comparison in
CalculateMALLUseForStaticScreen(), which blindly returns true.
This causes DML to calculate with is_using_mall_for_ss[n] = true.
Example:
0 + 0 <= 0 -> true
|
v
is_using_mall_for_ss[1] = true
|
v
use_one_row_for_frame[1] = true
PTE_BUFFER_MODE[1] = true
|
v
dpte_row_height : 128 -> 808
dpte_row_width_ub : 196,608 -> 1,204,224
|
+--> DST_Y_PER_PTE_ROW_NOM_L = 808
|
+--> N_groups = ceil(1,204,224 / 65,536 / 2) = 10
|
v
REFCYC_PER_PTE_GROUP_NOM_L = 8416 (0x20E0)
Currently, DML does not plumb out the programming for PTE_BUFFER_MODE and
FORCE_ONE_ROW_FOR_FRAME,
but even adding that programming does not enable the mode to work with these
values.
The simplest fix is to just block any opportunistic MALL calculations.
Reviewed-by: Dillon Varone <[email protected]>
Signed-off-by: Ovidiu Bunea <[email protected]>
Signed-off-by: Chenyu Chen <[email protected]>
---
.../dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git
a/drivers/gpu/drm/amd/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c
b/drivers/gpu/drm/amd/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c
index 47d63dd69a90..64afb67054d5 100644
---
a/drivers/gpu/drm/amd/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c
+++
b/drivers/gpu/drm/amd/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c
@@ -2001,6 +2001,10 @@ static void CalculateMALLUseForStaticScreen(
#endif
}
+ /* If no MALL is allocated for DCN, there is no need to calculate
usage for static screen. */
+ if (MALLAllocatedForDCN == 0)
+ return;
+
SurfaceToAddToMALL = 0;
CanAddAnotherSurfaceToMALL = true;
while (CanAddAnotherSurfaceToMALL) {
--
2.43.0
