[PATCH v2] HID: leave dev_rdesc unmodified and use it for comparisons

[Kevin Daughtridge]

The dev_rdesc member of the hid_device structure is meant to store the original
report descriptor received from the device, but it is currently passed to any
report_fixup method before it is copied to the rdesc member. This patch moves
the kmemdup to before, not after, the report_fixup call, keeping dev_rdesc
unchanged.

usbhid's hid_post_reset checks the report descriptor currently returned by the
device against a descriptor that may have been modified by a driver's
report_fixup method. That leaves some devices nonfunctional after a resume, with
a "reset_resume error 1" reported. This patch checks the new descriptor against
the unmodified dev_rdesc instead.

BugLink:http://bugs.launchpad.net/bugs/1049623
Signed-off-by: Kevin Daughtridge<kevin@xxxxxxxx>
---
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -775,12 +775,14 @@ int hid_open_report(struct hid_device *d
 		return -ENODEV;
 	size = device->dev_rsize;
 
+	start = kmemdup(start, size, GFP_KERNEL);
+	if (start == NULL)
+		return -ENOMEM;
+
 	if (device->driver->report_fixup)
 		start = device->driver->report_fixup(device, start, &size);
 
-	device->rdesc = kmemdup(start, size, GFP_KERNEL);
-	if (device->rdesc == NULL)
-		return -ENOMEM;
+	device->rdesc = start;
 	device->rsize = size;
 
 	parser = vzalloc(sizeof(struct hid_parser));
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -1436,7 +1436,7 @@ static int hid_post_reset(struct usb_int
 		kfree(rdesc);
 		return 1;
 	}
-	status = memcmp(rdesc, hid->rdesc, hid->rsize);
+	status = memcmp(rdesc, hid->dev_rdesc, hid->rsize);
 	kfree(rdesc);
 	if (status != 0) {
 		dbg_hid("report descriptor changed\n");

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