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Tue, 11 Aug 2026 02:10:54 -0700 (PDT) Message-ID: <7d4a7f0c-2b0e-471e-9c29-867bae981523@linaro.org> Date: Tue, 11 Aug 2026 10:10:53 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] coresight: trbe: Hide enable_sink sysfs file To: Leo Yan Cc: Suzuki K Poulose , Mike Leach , Yeoreum Yun , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260807-james-cs-hide-trbe-enable-v2-1-0b2af223feed@linaro.org> <20260811090424.GD15499@e132581.arm.com> Content-Language: en-US From: James Clark In-Reply-To: <20260811090424.GD15499@e132581.arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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 > > Reviewed-by: Leo Yan