[PATCH oneiric] SRU: Kernel does not report some USB printers correctly, making them not being detected by CUPS

[Till Kamppeter]

Already sent to upstream by someone else, and waiting for approval:

https://lkml.org/lkml/2011/9/25/57
https://lkml.org/lkml/2011/9/26/371

BugLink: https://bugs.launchpad.net/bugs/872711

SRU Justification:

Many printers, including

- HP Color LaserJet CM3530 MFP
- Xerox Phaser 3100MPF
- HP LaserJet 1200
- HP DeskJet 959C
- HP DeskJet 842C
- Canon IP6700D
- Prolific USB->Centronics cable (067b:2305)

are not detected by the USB backend of CUPS and so they (at least the 
non-HP devices, as the HP devices are recognized by HPLIP) are not able 
to print under Oneiric. Under Natty and earlier they work. This is a 
regression.

See also http://www.cups.org/str.php?L3884.

Patch pasted in below and attached.

    Till

----------

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 37518df..1d73709 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -607,9 +607,10 @@ static int findintfep(struct usb_device *dev, 
unsigned int ep)
  }

  static int check_ctrlrecip(struct dev_state *ps, unsigned int requesttype,
-			   unsigned int index)
+			   unsigned int request, unsigned int index)
  {
  	int ret = 0;
+	struct usb_host_interface *alt_setting;

  	if (ps->dev->state != USB_STATE_UNAUTHENTICATED
  	 && ps->dev->state != USB_STATE_ADDRESS
@@ -618,6 +619,19 @@ static int check_ctrlrecip(struct dev_state *ps, 
unsigned int requesttype,
  	if (USB_TYPE_VENDOR == (USB_TYPE_MASK & requesttype))
  		return 0;

+	/*
+	 * check for the special corner case 'get_device_id' in the printer
+	 * class specification, where wIndex is (interface << 8 | altsetting)
+	 * instead of just interface
+	 */
+	if (requesttype == 0xa1 && request == 0) {
+		alt_setting = usb_find_alt_setting(ps->dev->actconfig,
+						   index >> 8, index & 0xff);
+		if (alt_setting
+		 && alt_setting->desc.bInterfaceClass == USB_CLASS_PRINTER)
+			index >>= 8;
+	}
+
  	index &= 0xff;
  	switch (requesttype & USB_RECIP_MASK) {
  	case USB_RECIP_ENDPOINT:
@@ -770,7 +784,8 @@ static int proc_control(struct dev_state *ps, void 
__user *arg)

  	if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
  		return -EFAULT;
-	ret = check_ctrlrecip(ps, ctrl.bRequestType, ctrl.wIndex);
+	ret = check_ctrlrecip(ps, ctrl.bRequestType, ctrl.bRequest,
+			      ctrl.wIndex);
  	if (ret)
  		return ret;
  	wLength = ctrl.wLength;		/* To suppress 64k PAGE_SIZE warning */
@@ -1100,7 +1115,7 @@ static int proc_do_submiturb(struct dev_state *ps, 
struct usbdevfs_urb *uurb,
  			kfree(dr);
  			return -EINVAL;
  		}
-		ret = check_ctrlrecip(ps, dr->bRequestType,
+		ret = check_ctrlrecip(ps, dr->bRequestType, dr->bRequest,
  				      le16_to_cpup(&dr->wIndex));
  		if (ret) {
  			kfree(dr);
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