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From:   Ricardo Ribalda <ribalda@chromium.org>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        tfiga@chromium.org
Cc:     Ricardo Ribalda <ribalda@chromium.org>
Subject: [PATCH v10 16/21] media: docs: Document the behaviour of uvcvideo driver
Date:   Fri, 18 Jun 2021 14:29:18 +0200
Message-Id: <20210618122923.385938-17-ribalda@chromium.org>
In-Reply-To: <20210618122923.385938-1-ribalda@chromium.org>
References: <20210618122923.385938-1-ribalda@chromium.org>
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The uvc driver relies on the camera firmware to keep the control states
and therefore is not capable of changing an inactive control.

Allow returning -EACCES in those cases.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst      | 3 +++
 Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst
index 80e8c63d530f..fd09677f64f8 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst
@@ -95,3 +95,6 @@ EBUSY
 
 EACCES
     Attempt to set a read-only control or to get a write-only control.
+
+    Or if there is an attempt to set an inactive control and the driver is
+    not capable of caching the new value until the control is active again.
diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
index 3ba22983d21f..b42b822e9ede 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
@@ -458,3 +458,6 @@ EACCES
 
     Or the ``which`` field was set to ``V4L2_CTRL_WHICH_REQUEST_VAL`` but the
     device does not support requests.
+
+    Or if there is an attempt to set an inactive control and the driver is
+    not capable of caching the new value until the control is active again.
-- 
2.32.0.288.g62a8d224e6-goog