From: Bjorn Andersson quic_bjorande@quicinc.com
stable inclusion from stable-v6.6.4 commit 405b4f6d211345b1be64df938ef980e816519af3 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8N1WC
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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@vger.kernel.org Suggested-by: Doug Anderson dianders@chromium.org Suggested-by: Rob Clark robdclark@chromium.org Signed-off-by: Bjorn Andersson quic_bjorande@quicinc.com Tested-by: Johan Hovold johan+linaro@kernel.org Tested-by: Steev Klimaszewski steev@kali.org Reviewed-by: Abhinav Kumar quic_abhinavk@quicinc.com Patchwork: https://patchwork.freedesktop.org/patch/565094/ Link: https://lore.kernel.org/r/20231030-sc8280xp-dpu-safe-lut-v1-1-6d485d7b428f@q... Signed-off-by: Abhinav Kumar quic_abhinavk@quicinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_8_0_sc8280xp.h | 1 + 1 file changed, 1 insertion(+)
diff --git 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 index 58f5e25679b1..ff9adb8000ac 100644 --- 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 sc8280xp_perf_data = { .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