Hello Simon Haggett,
The patch dc3c78e43469: "HID: usbhid: Check HID report descriptor
contents after device reset" from Apr 3, 2012, leads to the following
static checker warning:
drivers/hid/usbhid/hid-core.c:1591 hid_reset_resume()
warn: bool comparison is always 'true'
drivers/hid/usbhid/hid-core.c
1421 static int hid_post_reset(struct usb_interface *intf)
1422 {
1423 struct usb_device *dev = interface_to_usbdev (intf);
1424 struct hid_device *hid = usb_get_intfdata(intf);
1425 struct usbhid_device *usbhid = hid->driver_data;
1426 struct usb_host_interface *interface = intf->cur_altsetting;
1427 int status;
1428 char *rdesc;
1429
1430 /* Fetch and examine the HID report descriptor. If this
1431 * has changed, then rebind. Since usbcore's check of the
1432 * configuration descriptors passed, we already know that
1433 * the size of the HID report descriptor has not changed.
1434 */
1435 rdesc = kmalloc(hid->dev_rsize, GFP_KERNEL);
1436 if (!rdesc) {
1437 dbg_hid("couldn't allocate rdesc memory
(post_reset)\n");
1438 return 1;
We return 1 on error now in this function. I can't figure out if this
is intentional.
1439 }
1440 status = hid_get_class_descriptor(dev,
1441 interface->desc.bInterfaceNumber,
1442 HID_DT_REPORT, rdesc, hid->dev_rsize);
1443 if (status < 0) {
1444 dbg_hid("reading report descriptor failed
(post_reset)\n");
1445 kfree(rdesc);
1446 return 1;
1447 }
1448 status = memcmp(rdesc, hid->dev_rdesc, hid->dev_rsize);
1449 kfree(rdesc);
1450 if (status != 0) {
1451 dbg_hid("report descriptor changed\n");
1452 return 1;
1453 }
1454
1455 spin_lock_irq(&usbhid->lock);
1456 clear_bit(HID_RESET_PENDING, &usbhid->iofl);
1457 spin_unlock_irq(&usbhid->lock);
1458 hid_set_idle(dev, intf->cur_altsetting->desc.bInterfaceNumber,
0, 0);
1459 status = hid_start_in(hid);
1460 if (status < 0)
1461 hid_io_error(hid);
1462 usbhid_restart_queues(usbhid);
Because we hit an error then we don't do this stuff.
1463
1464 return 0;
1465 }
[ snip ]
1589 clear_bit(HID_SUSPENDED, &usbhid->iofl);
1590 status = hid_post_reset(intf);
1591 if (status >= 0 && hid->driver && hid->driver->reset_resume) {
^^^^^^^^^^^
This condition is always true.
1592 int ret = hid->driver->reset_resume(hid);
1593 if (ret < 0)
1594 status = ret;
Maybe the ->reset_resume() can succeed even though hid_post_reset()
failed? In that case, we return the "1" error code and print it in
dmesg in usb_resume_interface(). Strange and uncommented.
1595 }
1596 return status;
1597 }
regards,
dan carpenter
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