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 v8 17/19] media: docs: Document the behaviour of uvcdriver
Date: Fri, 19 Mar 2021 18:09:04 +0100 [thread overview]
Message-ID: <20210319170906.278238-18-ribalda@chromium.org> (raw)
In-Reply-To: <20210319170906.278238-1-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.rc2.261.g7f71774620-goog
next prev parent reply other threads:[~2021-03-19 17:10 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 17:08 [PATCH v8 00/19] uvcvideo: Fix v4l2-compliance errors Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 01/19] media: v4l2-ioctl: Fix check_ext_ctrls Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 02/19] media: pvrusb2: Do not check for V4L2_CTRL_WHICH_DEF_VAL Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 03/19] media: uvcvideo: " Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 04/19] media: v4l2-ioctl: S_CTRL output the right value Ricardo Ribalda
2021-03-20 7:24 ` Hans Verkuil
2021-03-19 17:08 ` [PATCH v8 05/19] media: uvcvideo: Remove s_ctrl and g_ctrl Ricardo Ribalda
2021-03-20 7:25 ` Hans Verkuil
2021-03-19 17:08 ` [PATCH v8 06/19] media: uvcvideo: Set capability in s_param Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 07/19] media: uvcvideo: Return -EIO for control errors Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 08/19] media: uvcvideo: refactor __uvc_ctrl_add_mapping Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 09/19] media: uvcvideo: Add support for V4L2_CTRL_TYPE_CTRL_CLASS Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 10/19] media: uvcvideo: Use dev->name for querycap() Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 11/19] media: uvcvideo: Set unique vdev name based in type Ricardo Ribalda
2021-03-19 17:08 ` [PATCH v8 12/19] media: uvcvideo: Increase the size of UVC_METADATA_BUF_SIZE Ricardo Ribalda
2021-03-19 17:09 ` [PATCH v8 13/19] media: uvcvideo: Use control names from framework Ricardo Ribalda
2021-03-19 17:09 ` [PATCH v8 14/19] media: uvcvideo: Check controls flags before accessing them Ricardo Ribalda
2021-03-19 17:09 ` [PATCH v8 15/19] media: uvcvideo: Set error_idx during ctrl_commit errors Ricardo Ribalda
2021-03-20 7:27 ` Hans Verkuil
2021-03-19 17:09 ` [PATCH v8 16/19] media: uvcvideo: Return -EACCES to inactive controls Ricardo Ribalda
2021-03-19 17:09 ` Ricardo Ribalda [this message]
2021-03-19 17:09 ` [PATCH v8 18/19] media: uvcvideo: Downgrade control error messages Ricardo Ribalda
2021-03-19 17:09 ` [PATCH v8 19/19] uvc: use vb2 ioctl and fop helpers Ricardo Ribalda
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