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From:   Rob Clark <robdclark@gmail.com>
To:     dri-devel@lists.freedesktop.org
Cc:     freedreno@lists.freedesktop.org,
        Rob Clark <robdclark@chromium.org>,
        Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.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>,
        linux-arm-msm@vger.kernel.org (open list:DRM DRIVER FOR MSM ADRENO GPU),
        linux-kernel@vger.kernel.org (open list)
Subject: [RFC] drm/msm/rd: Check PT_PTRACED for cmdstream dumping
Date:   Thu, 14 Sep 2023 10:24:53 -0700
Message-ID: <20230914172453.9707-1-robdclark@gmail.com>
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From: Rob Clark <robdclark@chromium.org>

So, when you want to get a cmdstream trace of some deqp or piglit test,
but you happen to be running it on the same laptop with full desktop
env, the current dump-everything firehose of `cat $debugfs/dri/n/rd` is
quite a bit too much.  Ptrace seemed kind of a natural way to control
it, ie. either run what you want to trace under gdb or hack in a
ptrace(PTRACE_TRACEME) call.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/msm/msm_gem_submit.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index a908373cf34b..a105ca1f2102 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -979,7 +979,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 	/* The scheduler owns a ref now: */
 	msm_gem_submit_get(submit);
 
-	msm_rd_dump_submit(priv->rd, submit, NULL);
+	if (current->ptrace & PT_PTRACED)
+		msm_rd_dump_submit(priv->rd, submit, NULL);
 
 	pm_runtime_get_sync(&gpu->pdev->dev);
 
-- 
2.41.0