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From: Ricardo Ribalda <ribalda@chromium.org>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	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 v9 17/22] media: docs: Document the behaviour of uvcdriver
Date: Fri, 26 Mar 2021 10:58:35 +0100	[thread overview]
Message-ID: <20210326095840.364424-18-ribalda@chromium.org> (raw)
In-Reply-To: <20210326095840.364424-1-ribalda@chromium.org>

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 -EACESS in those cases.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst      | 5 +++++
 Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst
index 4f1bed53fad5..8c0a203385c2 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst
@@ -95,3 +95,8 @@ 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 keeping the new value until the control is active again.
+    This is the case for drivers that do not use the standard control
+    framework and rely purely on the hardware to keep the controls' state.
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 b9c62affbb5a..bb7de7a25241 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
@@ -438,3 +438,8 @@ 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 keeping the new value until the control is active again.
+    This is the case for drivers that do not use the standard control
+    framework and rely purely on the hardware to keep the controls' state.
-- 
2.31.0.291.g576ba9dcdaf-goog


  parent reply	other threads:[~2021-03-26 10:00 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26  9:58 [PATCH v9 00/22] uvcvideo: Fix v4l2-compliance errors Ricardo Ribalda
2021-03-26  9:58 ` [PATCH v9 01/22] media: v4l2-ioctl: Fix check_ext_ctrls Ricardo Ribalda
2021-06-10 16:19   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 02/22] media: pvrusb2: Do not check for V4L2_CTRL_WHICH_DEF_VAL Ricardo Ribalda
2021-06-10 17:29   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 03/22] media: uvcvideo: " Ricardo Ribalda
2021-06-10 16:21   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 04/22] media: v4l2-ioctl: S_CTRL output the right value Ricardo Ribalda
2021-06-10 16:23   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 05/22] media: uvcvideo: Remove s_ctrl and g_ctrl Ricardo Ribalda
2021-06-10 16:24   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 06/22] media: uvcvideo: Set capability in s_param Ricardo Ribalda
2021-03-26  9:58 ` [PATCH v9 07/22] media: uvcvideo: Return -EIO for control errors Ricardo Ribalda
2021-03-26  9:58 ` [PATCH v9 08/22] media: uvcvideo: refactor __uvc_ctrl_add_mapping Ricardo Ribalda
2021-03-26  9:58 ` [PATCH v9 09/22] media: uvcvideo: Add support for V4L2_CTRL_TYPE_CTRL_CLASS Ricardo Ribalda
2021-06-10 16:42   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 10/22] media: uvcvideo: Use dev->name for querycap() Ricardo Ribalda
2021-06-10 16:44   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 11/22] media: uvcvideo: Set unique vdev name based in type Ricardo Ribalda
2021-06-10 16:45   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 12/22] media: uvcvideo: Increase the size of UVC_METADATA_BUF_SIZE Ricardo Ribalda
2021-06-10 16:48   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 13/22] media: uvcvideo: Use control names from framework Ricardo Ribalda
2021-06-10 16:50   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 14/22] media: uvcvideo: Check controls flags before accessing them Ricardo Ribalda
2021-06-10 16:55   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 15/22] media: uvcvideo: Set error_idx during ctrl_commit errors Ricardo Ribalda
2021-06-10 17:05   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 16/22] media: uvcvideo: Return -EACCES to inactive controls Ricardo Ribalda
2021-03-27 11:23   ` Hans Verkuil
2021-06-10 17:28   ` Laurent Pinchart
2021-06-10 18:40     ` Ricardo Ribalda
2021-06-10 19:47       ` Ricardo Ribalda Delgado
2021-03-26  9:58 ` Ricardo Ribalda [this message]
2021-03-27 11:19   ` [PATCH v9 17/22] media: docs: Document the behaviour of uvcdriver Hans Verkuil
2021-03-27 12:01     ` Ricardo Ribalda
2021-03-27 12:03       ` Hans Verkuil
2021-06-10 17:08       ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 18/22] media: uvcvideo: Downgrade control error messages Ricardo Ribalda
2021-03-27 11:19   ` Hans Verkuil
2021-06-10 16:59   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 19/22] uvcvideo: uvc_ctrl_is_accessible: check for INACTIVE Ricardo Ribalda
2021-03-27 12:26   ` Ricardo Ribalda Delgado
2021-03-26  9:58 ` [PATCH v9 20/22] uvcvideo: improve error handling in uvc_query_ctrl() Ricardo Ribalda
2021-06-10 17:14   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 21/22] uvcvideo: don't spam the log in uvc_ctrl_restore_values() Ricardo Ribalda
2021-06-10 16:57   ` Laurent Pinchart
2021-03-26  9:58 ` [PATCH v9 22/22] uvc: use vb2 ioctl and fop helpers Ricardo Ribalda
2021-04-02  2:50   ` Tomasz Figa
2021-05-25  8:06 ` [PATCH v9 00/22] uvcvideo: Fix v4l2-compliance errors Tomasz Figa

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