linux-kernel - Re: [PATCH 04/17] drm/msm/a6xx: Poll additional DRV status

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <9778efad-e9a8-4934-9b70-b0429bcfe63e@oss.qualcomm.com>
Date: Wed, 23 Jul 2025 12:01:06 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Akhil P Oommen <akhilpo@....qualcomm.com>,
        Rob Clark <robin.clark@....qualcomm.com>, Sean Paul <sean@...rly.run>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jessica.zhang@....qualcomm.com>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 04/17] drm/msm/a6xx: Poll additional DRV status

On 7/20/25 2:16 PM, Akhil P Oommen wrote:
> A7XX_GEN2 generation has additional TCS slots. Poll the respective
> DRV status registers before pm suspend.
> 
> Signed-off-by: Akhil P Oommen <akhilpo@....qualcomm.com>
> ---
>  drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> index 790ef2f94a0b0cd40433d7edb6a89e4f04408bf5..3bebb6dd7059782ceca29f2efd2acee24d3fc930 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> @@ -987,6 +987,22 @@ static void a6xx_gmu_rpmh_off(struct a6xx_gmu *gmu)
>  		val, (val & 1), 100, 10000);
>  	gmu_poll_timeout_rscc(gmu, REG_A6XX_RSCC_TCS3_DRV0_STATUS + seqmem_off,
>  		val, (val & 1), 100, 1000);
> +
> +	if (!adreno_is_a740_family(adreno_gpu))
> +		return;
> +
> +	gmu_poll_timeout_rscc(gmu, REG_A7XX_RSCC_TCS4_DRV0_STATUS + seqmem_off,
> +		val, (val & 1), 100, 10000);
> +	gmu_poll_timeout_rscc(gmu, REG_A7XX_RSCC_TCS5_DRV0_STATUS + seqmem_off,
> +		val, (val & 1), 100, 10000);
> +	gmu_poll_timeout_rscc(gmu, REG_A7XX_RSCC_TCS6_DRV0_STATUS + seqmem_off,
> +		val, (val & 1), 100, 10000);
> +	gmu_poll_timeout_rscc(gmu, REG_A7XX_RSCC_TCS7_DRV0_STATUS + seqmem_off,
> +		val, (val & 1), 100, 1000);
> +	gmu_poll_timeout_rscc(gmu, REG_A7XX_RSCC_TCS8_DRV0_STATUS + seqmem_off,
> +		val, (val & 1), 100, 10000);
> +	gmu_poll_timeout_rscc(gmu, REG_A7XX_RSCC_TCS9_DRV0_STATUS + seqmem_off,
> +		val, (val & 1), 100, 1000);

FWIW there are places downstream where it polls for 1 ms
(gen7_gmu_pwrctrl_suspend) / 2 ms (gen7_gmu_power_off) ms (as opposed
to 1 or 10 ms here), but the timeouts are all the same across registers
(unlike TCS3 and TCS9 above)

Ultimately it's a timeout, so a value too big shouldn't matter, but
let's make sure the other threshold is ok

Konrad