6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
commit a33b2431d11b4df137bbcfdd5a5adfa054c2479e upstream.
During USB transfers on the SC8280XP __arm_smmu_tlb_sync() is seen to
typically take 1-2ms to complete. As expected this results in poor
performance, something that has been mitigated by proposing running the
iommu in non-strict mode (boot with iommu.strict=0).
This turns out to be related to the SAFE logic, and programming the QOS
SAFE values in the DPU (per suggestion from Rob and Doug) reduces the
TLB sync time to below 10us, which means significant less time spent
with interrupts disabled and a significant boost in throughput.
Fixes: 4a352c2fc15a ("drm/msm/dpu: Introduce SC8280XP")
Cc: stable@xxxxxxxxxxxxxxx
Suggested-by: Doug Anderson <dianders@xxxxxxxxxxxx>
Suggested-by: Rob Clark <robdclark@xxxxxxxxxxxx>
Signed-off-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
Tested-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
Tested-by: Steev Klimaszewski <steev@xxxxxxxx>
Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
Patchwork: https://patchwork.freedesktop.org/patch/565094/
Link: https://lore.kernel.org/r/20231030-sc8280xp-dpu-safe-lut-v1-1-6d485d7b428f@xxxxxxxxxxx
Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_8_0_sc8280xp.h | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_8_0_sc8280xp.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_8_0_sc8280xp.h
@@ -419,6 +419,7 @@ static const struct dpu_perf_cfg sc8280x
.min_llcc_ib = 0,
.min_dram_ib = 800000,
.danger_lut_tbl = {0xf, 0xffff, 0x0},
+ .safe_lut_tbl = {0xfe00, 0xfe00, 0xffff},
.qos_lut_tbl = {
{.nentry = ARRAY_SIZE(sc8180x_qos_linear),
.entries = sc8180x_qos_linear
