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([2001:a61:1346:4701:62aa:40c:8866:519d]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-483bfcbd781sm237871075e9.8.2026.03.02.02.27.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 02 Mar 2026 02:27:39 -0800 (PST) Message-ID: <46b003fb-c3b2-4ad6-a3a5-c73e2e248a26@suse.com> Date: Mon, 2 Mar 2026 11:27:23 +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] usb: cdc-acm: Restore CAP_BRK functionnality to CH343 To: Marc Zyngier , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org, Greg Kroah-Hartman References: <20260301124440.1192752-1-maz@kernel.org> Content-Language: en-US From: Oliver Neukum In-Reply-To: <20260301124440.1192752-1-maz@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 01.03.26 13:44, Marc Zyngier wrote: > The CH343 USB/serial adapter is as buggy as it is popular (very). > One of its quirks is that despite being capable of signalling a > BREAK condition, it doesn't advertise it. > > This used to work nonetheless until 66aad7d8d3ec5 ("usb: cdc-acm: > return correct error code on unsupported break") applied some > reasonable restrictions, preventing breaks from being emitted on > devices that do not advertise CAP_BRK. > > Add a quirk for this particular device, so that breaks can still > be produced on some of my machines attached to my console server. > > Fixes: 66aad7d8d3ec5 ("usb: cdc-acm: return correct error code on unsupported break") > Signed-off-by: Marc Zyngier > Cc: stable@vger.kernel.org > Cc: Oliver Neukum > Cc: Greg Kroah-Hartman Acked-by: Oliver Neukum