linux-kernel - Re: [PATCH v2 2/2] drm/msm: Hangcheck progress detection

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Date:   Thu, 3 Nov 2022 02:26:20 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Rob Clark <robdclark@...il.com>, dri-devel@...ts.freedesktop.org
Cc:     freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        Rob Clark <robdclark@...omium.org>,
        Akhil P Oommen <quic_akhilpo@...cinc.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Vladimir Lypak <vladimir.lypak@...il.com>,
        Douglas Anderson <dianders@...omium.org>,
        Chia-I Wu <olvaffe@...il.com>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] drm/msm: Hangcheck progress detection

On 02/11/2022 01:33, Rob Clark wrote:
> From: Rob Clark <robdclark@...omium.org>
> 
> If the hangcheck timer expires, check if the fw's position in the
> cmdstream has advanced (changed) since last timer expiration, and
> allow it up to three additional "extensions" to it's alotted time.
> The intention is to continue to catch "shader stuck in a loop" type
> hangs quickly, but allow more time for things that are actually
> making forward progress.

Just out of curiosity: wouldn't position also change for a 'shader stuck 
in a loop'?


> Because we need to sample the CP state twice to detect if there has
> not been progress, this also cuts the the timer's duration in half.
> 
> v2: Fix typo (REG_A6XX_CP_CSQ_IB2_STAT), add comment
> 
> Signed-off-by: Rob Clark <robdclark@...omium.org>
> Reviewed-by: Akhil P Oommen <quic_akhilpo@...cinc.com>



-- 
With best wishes
Dmitry