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Message-ID: <ad9f92d8-9aa6-14d1-7444-bb64131044b5@quicinc.com>
Date:   Wed, 15 Nov 2023 10:41:15 -0800
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Subject: Re: [PATCH] drm/msm/dpu: Add missing safe_lut_tbl in sc8280xp catalog
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To:     Bjorn Andersson <quic_bjorande@quicinc.com>,
        Rob Clark <robdclark@gmail.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        "Sean Paul" <sean@poorly.run>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        "David Airlie" <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Bjorn Andersson <andersson@kernel.org>,
        Kuogee Hsieh <quic_khsieh@quicinc.com>
CC:     Johan Hovold <johan@kernel.org>, <linux-arm-msm@vger.kernel.org>,
        <dri-devel@lists.freedesktop.org>,
        <freedreno@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>,
        <stable@vger.kernel.org>, Doug Anderson <dianders@chromium.org>,
        Rob Clark <robdclark@chromium.org>
References: <20231030-sc8280xp-dpu-safe-lut-v1-1-6d485d7b428f@quicinc.com>
From:   Abhinav Kumar <quic_abhinavk@quicinc.com>
In-Reply-To: <20231030-sc8280xp-dpu-safe-lut-v1-1-6d485d7b428f@quicinc.com>
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Precedence: bulk


On 10/30/2023 4:23 PM, Bjorn Andersson wrote:
> 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>
> ---

Matches what we have in downstream DT, hence

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.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 1ccd1edd693c..4c0528794e7a 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
> @@ -406,6 +406,7 @@ 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
> 
> ---
> base-commit: c503e3eec382ac708ee7adf874add37b77c5d312
> change-id: 20231030-sc8280xp-dpu-safe-lut-9769027b8452
> 
> Best regards,