From: James Clark <james.clark@linaro.org>
To: Leo Yan <leo.yan@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@arm.com>,
Yeoreum Yun <yeoreum.yun@arm.com>,
coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] coresight: trbe: Hide enable_sink sysfs file
Date: Tue, 11 Aug 2026 10:10:53 +0100 [thread overview]
Message-ID: <7d4a7f0c-2b0e-471e-9c29-867bae981523@linaro.org> (raw)
In-Reply-To: <20260811090424.GD15499@e132581.arm.com>
On 11/08/2026 10:04, Leo Yan wrote:
> On Fri, Aug 07, 2026 at 11:13:22AM +0100, James Clark wrote:
>> TRBE doesn't support sysfs mode, but the enable_sink file can still be
>> successfully written to enable the device, and only attempting to enable
>> the source would later fail.
>>
>> Avoid misleading users by adding a flag that devices can use to hide
>> either the enable_sink or enable_source files, and set it for TRBE.
>>
>> Don't set it for ETE as it's possible that ETE could appear on the
>> legacy bus and work with sysfs, and writing to enable_source already
>> reports EINVAL if the device doesn't support sysfs mode.
>
> It is a pity that we cannot determine from the ETE registers whether ETE
> is connected to the legacy bus or TRBE.
>
We could determine it from the device tree. A path has to be built or
you can't use it on the legacy bus either. Maybe we can do a more
general change in the future to hide the flag for any non-connected CPU
source.
>> Signed-off-by: James Clark <james.clark@linaro.org>
>
> Reviewed-by: Leo Yan <leo.yan@arm.com>
next prev parent reply other threads:[~2026-08-11 9:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-07 10:13 James Clark
2026-08-11 9:04 ` Leo Yan
2026-08-11 9:10 ` James Clark [this message]
2026-08-11 9:17 ` Suzuki K Poulose
2026-10-01 14:10 ` Suzuki K Poulose
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