On Sun, 8 Jul 2012, Eric Ding wrote:
> >> I think the reason was the way rpm_suspend() worked at the time of that
> >> commit (it works a bit differently now, but not as much as to avoid the
> >> problem).
> >>
> >> Namely, before commit e1620d591a75a10b15cf61dbf8243a0b7e6731a2 the device
> >> had a device type without runtime PM callbacks. So, rpm_suspend() saw
> >> that dev->type was set and dev->type->pm was set, so it assigned NULL to
> >> callback. As a result, nothing happened when rpm_callback(callback, dev)
> >> was run.
> >
> > I don't follow. If that were the reason then no USB device would have
> > been runtime-suspended before the e1620d commit.
> >
> > Are you saying this actually was true for some period of time (such as
> > between the commit that added the "callback" variable and the e1620d
> > commit)?
>
> I think this is, in fact, what happened. See rpm_suspend() before and
> after commit 9659cc0; I suspect that between commit 9659cc0 and commit
> e1620d5, no USB device was being runtime-suspended. Since this was
> after v2.6.38 and before v2.6.39-rc1, though, it wouldn't have been
> widely seen or tested, right?
I guess so. That would explain it.
> However, that doesn't fully explain why the webcam wouldn't have been
> autosuspended in v2.6.38 -- perhaps you all can guess at this more
> quickly than I can? Was enough changed in the runtime PM architecture
> from v2.6.38 to e1620d to explain this difference?
I don't know... And at this point I don't care very much about what
was going on in 2.6.38 or before.
In the meantime, can you try out this patch in place of your own? (I
haven't even tried to compile it, so there may be one or two small
errors.)
Alan Stern
Index: usb-3.5/drivers/media/video/uvc/uvc_driver.c
===================================================================
--- usb-3.5.orig/drivers/media/video/uvc/uvc_driver.c
+++ usb-3.5/drivers/media/video/uvc/uvc_driver.c
@@ -29,6 +29,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
+#include <linux/usb/quirks.h>
#include <linux/videodev2.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
@@ -49,6 +50,8 @@ static unsigned int uvc_quirks_param = -
unsigned int uvc_trace_param;
unsigned int uvc_timeout_param = UVC_CTRL_STREAMING_TIMEOUT;
+#define USB_VENDOR_LOGITECH 0x046d
+
/* ------------------------------------------------------------------------
* Video formats
*/
@@ -1813,6 +1816,16 @@ static int uvc_probe(struct usb_interfac
uvc_trace(UVC_TRACE_PROBE, "Probing generic UVC device %s\n",
udev->devpath);
+ /* Many Logitech webcams require the RESET_RESUME quirk */
+ if (le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_LOGITECH) {
+ udev->quirks |= USB_QUIRK_RESET_RESUME;
+ dev_dbg(&udev->dev, "adding reset-resume quirk\n");
+
+ /* Do a device reset, in case the device was just resumed */
+ if (usb_reset_device(udev) < 0)
+ return -EIO;
+ }
+
/* Allocate memory for the device and initialize it. */
if ((dev = kzalloc(sizeof *dev, GFP_KERNEL)) == NULL)
return -ENOMEM;
Index: usb-3.5/drivers/usb/core/quirks.c
===================================================================
--- usb-3.5.orig/drivers/usb/core/quirks.c
+++ usb-3.5/drivers/usb/core/quirks.c
@@ -38,54 +38,6 @@ static const struct usb_device_id usb_qu
/* Creative SB Audigy 2 NX */
{ USB_DEVICE(0x041e, 0x3020), .driver_info = USB_QUIRK_RESET_RESUME },
- /* Logitech Webcam C200 */
- { USB_DEVICE(0x046d, 0x0802), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C250 */
- { USB_DEVICE(0x046d, 0x0804), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C300 */
- { USB_DEVICE(0x046d, 0x0805), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam B/C500 */
- { USB_DEVICE(0x046d, 0x0807), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C600 */
- { USB_DEVICE(0x046d, 0x0808), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam Pro 9000 */
- { USB_DEVICE(0x046d, 0x0809), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C905 */
- { USB_DEVICE(0x046d, 0x080a), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C210 */
- { USB_DEVICE(0x046d, 0x0819), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C260 */
- { USB_DEVICE(0x046d, 0x081a), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C310 */
- { USB_DEVICE(0x046d, 0x081b), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C910 */
- { USB_DEVICE(0x046d, 0x0821), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C160 */
- { USB_DEVICE(0x046d, 0x0824), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Webcam C270 */
- { USB_DEVICE(0x046d, 0x0825), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Quickcam Pro 9000 */
- { USB_DEVICE(0x046d, 0x0990), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Quickcam E3500 */
- { USB_DEVICE(0x046d, 0x09a4), .driver_info = USB_QUIRK_RESET_RESUME },
-
- /* Logitech Quickcam Vision Pro */
- { USB_DEVICE(0x046d, 0x09a6), .driver_info = USB_QUIRK_RESET_RESUME },
-
/* Logitech Harmony 700-series */
{ USB_DEVICE(0x046d, 0xc122), .driver_info = USB_QUIRK_DELAY_INIT },
--
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