Hi Edgar,
Thank you for the patch.
On Thursday, 12 October 2017 10:54:17 EET Edgar Thier wrote:
> Use flags the device exposes for UVC controls.
> This allows the device to define which property flags are set.
>
> Since some cameras offer auto-adjustments for properties (e.g. auto-gain),
> the values of other properties (e.g. gain) can change in the camera.
> Examining the flags ensures that the driver is aware of such properties.
>
> Signed-off-by: Edgar Thier <info@xxxxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 64 +++++++++++++++++++++++++++----------
> 1 file changed, 49 insertions(+), 15 deletions(-)
Running scripts/checkpatch.pl on the patch produces the following warning and
errors.
WARNING: line over 80 characters
#83: FILE: drivers/media/usb/uvc/uvc_ctrl.c:1635:
+static int uvc_ctrl_get_flags(struct uvc_device *dev, const struct
uvc_control *ctrl,
ERROR: code indent should use tabs where possible
#140: FILE: drivers/media/usb/uvc/uvc_ctrl.c:1702:
+ ^I^Iret = flags;$
WARNING: please, no space before tabs
#140: FILE: drivers/media/usb/uvc/uvc_ctrl.c:1702:
+ ^I^Iret = flags;$
WARNING: please, no spaces at the start of a line
#140: FILE: drivers/media/usb/uvc/uvc_ctrl.c:1702:
+ ^I^Iret = flags;$
The last three should be fixed. The first one can sometimes be considered a
matter of taste, but in this case it's easy to fix so we should address it
too.
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c
> b/drivers/media/usb/uvc/uvc_ctrl.c index 20397aba..8f902a41 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1629,6 +1629,40 @@ static void uvc_ctrl_fixup_xu_info(struct uvc_device
> *dev, }
> }
>
> +/*
> + * Retrieve flags for a given control
> + */
> +static int uvc_ctrl_get_flags(struct uvc_device *dev, const struct
> uvc_control *ctrl,
> + const struct uvc_control_info *info)
> +{
> + u8 *data;
> + int ret = 0;
No need to initialize ret to 0.
> + int flags = 0;
> +
> + data = kmalloc(2, GFP_KERNEL);
> + if (data == NULL)
> + return -ENOMEM;
> +
> + ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum,
> + info->selector, data, 1);
> + if (ret < 0) {
> + uvc_trace(UVC_TRACE_CONTROL,
> + "GET_INFO failed on control %pUl/%u (%d).\n",
> + info->entity, info->selector, ret);
> + } else {
> + flags = UVC_CTRL_FLAG_GET_MIN | UVC_CTRL_FLAG_GET_MAX
> + | UVC_CTRL_FLAG_GET_RES | UVC_CTRL_FLAG_GET_DEF
> + | (data[0] & UVC_CONTROL_CAP_GET ?
> + UVC_CTRL_FLAG_GET_CUR : 0)
> + | (data[0] & UVC_CONTROL_CAP_SET ?
> + UVC_CTRL_FLAG_SET_CUR : 0)
> + | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
> + UVC_CTRL_FLAG_AUTO_UPDATE : 0);
> + }
> + kfree(data);
> + return flags;
So in case of failure you will return 0, and the caller will ignore the
failure. This changes the behaviour of uvc_ctrl_fill_xu_info() which I don't
think is a good idea. For uvc_ctrl_add_info(), on the other hand, ignoring
errors is probably good, as otherwise we could introduce regressions with
devices that don't implement GET_INFO properly on standard controls (the
driver currently doesn't query information for standard controls so doesn't
catch those devices).
> +}
> +
> /*
> * Query control information (size and flags) for XU controls.
> */
> @@ -1636,6 +1670,7 @@ static int uvc_ctrl_fill_xu_info(struct uvc_device
> *dev, const struct uvc_control *ctrl, struct uvc_control_info *info)
> {
> u8 *data;
> + int flags;
> int ret;
>
> data = kmalloc(2, GFP_KERNEL);
> @@ -1659,24 +1694,15 @@ static int uvc_ctrl_fill_xu_info(struct uvc_device
> *dev,
>
> info->size = le16_to_cpup((__le16 *)data);
>
> - /* Query the control information (GET_INFO) */
> - ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum,
> - info->selector, data, 1);
> - if (ret < 0) {
> + flags = uvc_ctrl_get_flags(dev, ctrl, info);
> +
No need for a blank line here.
> + if (flags < 0) {
> uvc_trace(UVC_TRACE_CONTROL,
> - "GET_INFO failed on control %pUl/%u (%d).\n",
> - info->entity, info->selector, ret);
> + "Failed to retrieve flags (%d).\n", ret);
> + ret = flags;
> goto done;
> }
> -
> - info->flags = UVC_CTRL_FLAG_GET_MIN | UVC_CTRL_FLAG_GET_MAX
> - | UVC_CTRL_FLAG_GET_RES | UVC_CTRL_FLAG_GET_DEF
> - | (data[0] & UVC_CONTROL_CAP_GET ?
> - UVC_CTRL_FLAG_GET_CUR : 0)
> - | (data[0] & UVC_CONTROL_CAP_SET ?
> - UVC_CTRL_FLAG_SET_CUR : 0)
> - | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
> - UVC_CTRL_FLAG_AUTO_UPDATE : 0);
> + info->flags = flags;
>
> uvc_ctrl_fixup_xu_info(dev, ctrl, info);
>
> @@ -1890,6 +1916,7 @@ static int uvc_ctrl_add_info(struct uvc_device *dev,
> struct uvc_control *ctrl, const struct uvc_control_info *info)
> {
> int ret = 0;
> + int flags = 0;
There's no need to initialize the flags variable to 0.
>
> ctrl->info = *info;
> INIT_LIST_HEAD(&ctrl->info.mappings);
> @@ -1902,6 +1929,13 @@ static int uvc_ctrl_add_info(struct uvc_device *dev,
> struct uvc_control *ctrl, goto done;
> }
>
> + flags = uvc_ctrl_get_flags(dev, ctrl, info);
> + if (flags < 0)
> + uvc_trace(UVC_TRACE_CONTROL,
> + "Failed to retrieve flags (%d).\n", ret);
> + else
> + ctrl->info.flags = flags;
> +
> ctrl->initialized = 1;
>
> uvc_trace(UVC_TRACE_CONTROL, "Added control %pUl/%u to device %s "
All these are small issues. Let me try to address them, I'll send you an
updated patch shortly.
--
Regards,
Laurent Pinchart
