From: Leo Yan <leo.yan@arm.com>
To: Yuanfang Zhang <quic_yuanfang@quicinc.com>
Cc: James Clark <james.clark@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
kernel@oss.qualcomm.com, coresight@lists.linaro.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Alexander Shishkin <alexander.shishkin@linux.intel.com>
Subject: Re: [PATCH] coresight-tmc: Add configurable timeout for flush and tmcready
Date: Mon, 30 Jun 2025 12:08:36 +0100 [thread overview]
Message-ID: <20250630110836.GT794930@e132581.arm.com> (raw)
In-Reply-To: <5f2527d2-be55-411b-a79b-f628e9fe7f06@quicinc.com>
On Mon, Jun 30, 2025 at 06:40:53PM +0800, Yuanfang Zhang wrote:
[...]
> >>> The current implementation uses a fixed timeout via
> >>> coresight_timeout(), which may be insufficient when multiple
> >>> sources are enabled or under heavy load, leading to TMC
> >>> readiness or flush completion timeout.
> >
> > I would suggest that we first make clear if this is a hardware quirk or
> > a common issue in Arm CoreSight.
> sure, now this issue has been found that not only CPU ETM, but also subsystem ETM.
As the commit log states, "sources are enabled or under heavy load,
leading to TMC readiness or flush completion timeout." I would like to
confirm how this situation can happen.
When disabling a CoreSight path, the driver follows a sequential
order: the source device is disabled first, followed by flushing and
disabling the TMC. We expect that there should be no contention
between source devices and the sink when disabling the path. For a
subsystem ETM, I expect we should also follow this sequence.
Leo
next prev parent reply other threads:[~2025-06-30 11:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-27 11:10 Yuanfang Zhang
2025-06-27 11:23 ` James Clark
2025-06-27 14:17 ` Leo Yan
2025-06-30 10:40 ` Yuanfang Zhang
2025-06-30 11:08 ` Leo Yan [this message]
2025-07-03 8:23 ` Yuanfang Zhang
2025-06-30 10:03 ` Yuanfang Zhang
2025-06-30 13:46 ` James Clark
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