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Mon, 26 May 2025 06:12:40 -0700 (PDT) X-Google-Smtp-Source: AGHT+IH8QvnLtVJhSpJ26PCw53K12teQU0kcApIkCEK6+L/O1mhz5DN4sVNTnhfSEoC9TKB9oRBNBA== X-Received: by 2002:a17:907:e98a:b0:ad5:3a7b:de91 with SMTP id a640c23a62f3a-ad85b1bfa4amr972799866b.27.1748265160087; Mon, 26 May 2025 06:12:40 -0700 (PDT) Received: from [10.40.98.122] ([78.108.130.194]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ad52d04b059sm1702170766b.10.2025.05.26.06.12.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 26 May 2025 06:12:39 -0700 (PDT) Message-ID: Date: Mon, 26 May 2025 15:12:39 +0200 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 v5 2/4] media: Documentation: Add note about UVCH length field To: Ricardo Ribalda , Laurent Pinchart , Mauro Carvalho Chehab , Guennadi Liakhovetski Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250404-uvc-meta-v5-0-f79974fc2d20@chromium.org> <20250404-uvc-meta-v5-2-f79974fc2d20@chromium.org> Content-Language: en-US, nl From: Hans de Goede In-Reply-To: <20250404-uvc-meta-v5-2-f79974fc2d20@chromium.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, On 4-Apr-25 08:37, Ricardo Ribalda wrote: > The documentation currently describes the UVC length field as the "length > of the rest of the block", which can be misleading. The driver limits the > data copied to a maximum of 12 bytes. > > This change adds a clarifying sentence to the documentation to make this > restriction explicit. > > Signed-off-by: Ricardo Ribalda Thanks, patch looks good to me: Reviewed-by: Hans de Goede Regards, Hans > --- > Documentation/userspace-api/media/v4l/metafmt-uvc.rst | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/Documentation/userspace-api/media/v4l/metafmt-uvc.rst b/Documentation/userspace-api/media/v4l/metafmt-uvc.rst > index 784346d14bbdbf28348262084d5b0646d30bd1da..42599875331c0066cf529153caccb731148023b9 100644 > --- a/Documentation/userspace-api/media/v4l/metafmt-uvc.rst > +++ b/Documentation/userspace-api/media/v4l/metafmt-uvc.rst > @@ -44,7 +44,9 @@ Each individual block contains the following fields: > them > * - :cspan:`1` *The rest is an exact copy of the UVC payload header:* > * - __u8 length; > - - length of the rest of the block, including this field > + - length of the rest of the block, including this field. Please note that > + regardless of the this value, for V4L2_META_FMT_UVC the kernel will > + never copy more than 2-12 bytes. > * - __u8 flags; > - Flags, indicating presence of other standard UVC fields > * - __u8 buf[]; >