HID: wacom: Have wacom_{get,set}_report retry on -EAGAIN, not -EPIPE

Retrying on -EPIPE makes very little sense since this typically indicates
a problem that will not just disappear on its own. For instance, the USB
documentation states that it will be sent if the endpoint is stalled or
the device has disconnected. Instead, we should retry if -EAGAIN is
received since this indicates a temporary error condition such as a busy
bus.

In addition to adjusting the conditions we retry under, we also log an
error on failure so that we can be aware of what's going on.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 7abf52caa8d81000997c3fa6efae8e818ae0764f..109312f9d3de082ffed0806b3a90a32a943bc6b1 100644 (file)
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -35,7 +35,11 @@ static int wacom_get_report(struct hid_device *hdev, u8 type, u8 *buf,
        do {
                retval = hid_hw_raw_request(hdev, buf[0], buf, size, type,
                                HID_REQ_GET_REPORT);
-       } while ((retval == -ETIMEDOUT || retval == -EPIPE) && --retries);
+       } while ((retval == -ETIMEDOUT || retval == -EAGAIN) && --retries);
+
+       if (retval < 0)
+               hid_err(hdev, "wacom_get_report: ran out of retries "
+                       "(last error = %d)\n", retval);
 
        return retval;
 }
@@ -48,7 +52,11 @@ static int wacom_set_report(struct hid_device *hdev, u8 type, u8 *buf,
        do {
                retval = hid_hw_raw_request(hdev, buf[0], buf, size, type,
                                HID_REQ_SET_REPORT);
-       } while ((retval == -ETIMEDOUT || retval == -EPIPE) && --retries);
+       } while ((retval == -ETIMEDOUT || retval == -EAGAIN) && --retries);
+
+       if (retval < 0)
+               hid_err(hdev, "wacom_set_report: ran out of retries "
+                       "(last error = %d)\n", retval);
 
        return retval;
 }