Hi Daniel, Thank you for the patch and sorry for the late response. On Thursday 12 March 2015 14:59:07 Daniel Drake wrote: > The Quanta NL3 laptop has a UVC camera which the descriptor says > comes from Realtek: https://gist.github.com/dsd/9a6567baa53c747fd306 > > Probe fails, because the output terminal (ID 3) references a > non-existent source with ID 6. Fixing it to add itself onto the > end of the chain makes the camera work. I knew a device with broken descriptors would come one day. It actually took much longer than I expected. I'm not sure that adding a device-specific quirk is the bast way to handle this problem, as it wouldn't really scale if other devices expose buggy descriptors. A more generic way to patch or override descriptors might be better, with a single quirk and a pointer to a patch function. This would require refactoring the quirks system to store a structure pointer instead of a bitfield in the driver_info field. What's your opinion ? > Signed-off-by: Daniel Drake <drake@xxxxxxxxxxxx> > --- > drivers/media/usb/uvc/uvc_driver.c | 36 +++++++++++++++++++++++++++++++++++ > drivers/media/usb/uvc/uvcvideo.h | 1 + > 2 files changed, 37 insertions(+) > > diff --git a/drivers/media/usb/uvc/uvc_driver.c > b/drivers/media/usb/uvc/uvc_driver.c index cf27006..3cb4be3 100644 > --- a/drivers/media/usb/uvc/uvc_driver.c > +++ b/drivers/media/usb/uvc/uvc_driver.c > @@ -1575,6 +1575,30 @@ static const char *uvc_print_chain(struct > uvc_video_chain *chain) } > > /* > + * This Realtek camera has a broken descriptor. The output terminal > + * references a non-existent source. The rest of the simple chain is > + * fine. Fix the OT to chain on to the end. > + */ > +static void uvc_handle_rtl57a7(struct uvc_device *dev) > +{ > + struct uvc_entity *term; > + > + term = uvc_entity_by_id(dev, 3); > + if (!term) { > + uvc_printk(KERN_INFO, "RTL57A7: no entity with id 3\n"); > + return; > + } > + > + if (!UVC_ENTITY_IS_OTERM(term)) { > + uvc_printk(KERN_INFO, "RTL57A7: entity 3 is not OT\n"); > + return; > + } > + > + term->baSourceID[0] = 4; > + uvc_printk(KERN_INFO, "Applied RTL57A7 chain quirk.\n"); > +} > + > +/* > * Scan the device for video chains and register video devices. > * > * Chains are scanned starting at their output terminals and walked > backwards. @@ -1584,6 +1608,9 @@ static int uvc_scan_device(struct > uvc_device *dev) struct uvc_video_chain *chain; > struct uvc_entity *term; > > + if (dev->quirks & UVC_QUIRK_RTL57A7) > + uvc_handle_rtl57a7(dev); > + > list_for_each_entry(term, &dev->entities, list) { > if (!UVC_ENTITY_IS_OTERM(term)) > continue; > @@ -2351,6 +2378,15 @@ static struct usb_device_id uvc_ids[] = { > .bInterfaceSubClass = 1, > .bInterfaceProtocol = 0, > .driver_info = UVC_QUIRK_PROBE_MINMAX }, > + /* Realtek camera in Quanta NL3 laptop */ > + { .match_flags = USB_DEVICE_ID_MATCH_DEVICE > + | USB_DEVICE_ID_MATCH_INT_INFO, > + .idVendor = 0x0bda, > + .idProduct = 0x57a7, > + .bInterfaceClass = USB_CLASS_VIDEO, > + .bInterfaceSubClass = 1, > + .bInterfaceProtocol = 0, > + .driver_info = UVC_QUIRK_RTL57A7 }, > /* MT6227 */ > { .match_flags = USB_DEVICE_ID_MATCH_DEVICE > > | USB_DEVICE_ID_MATCH_INT_INFO, > > diff --git a/drivers/media/usb/uvc/uvcvideo.h > b/drivers/media/usb/uvc/uvcvideo.h index c63e5b5..710e480 100644 > --- a/drivers/media/usb/uvc/uvcvideo.h > +++ b/drivers/media/usb/uvc/uvcvideo.h > @@ -152,6 +152,7 @@ > #define UVC_QUIRK_RESTRICT_FRAME_RATE 0x00000200 > #define UVC_QUIRK_RESTORE_CTRLS_ON_INIT 0x00000400 > #define UVC_QUIRK_FORCE_Y8 0x00000800 > +#define UVC_QUIRK_RTL57A7 0x00001000 > > /* Format flags */ > #define UVC_FMT_FLAG_COMPRESSED 0x00000001 -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
