Hi Edgar, A few more comments.
On Tuesday, 2 January 2018 22:07:24 EET Laurent Pinchart wrote: > 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 <i...@edgarthier.net> > > --- > > > > 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); Isn't 1 byte enough ? > > + if (data == NULL) > > + return -ENOMEM; > > + > > + ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum, > > + info->selector, data, 1); Indentation is incorrect here. > > + if (ret < 0) { > > + uvc_trace(UVC_TRACE_CONTROL, > > + "GET_INFO failed on control %pUl/%u (%d).\n", > > + info->entity, info->selector, ret); And here too. > > + } 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