Thread (8 messages) 8 messages, 3 authors, 2015-05-21

Re: [PATCH 1/2] HID: wacom: Allow wacom_{get,set}_report to retry on -EAGAIN

From: Benjamin Tissoires <hidden>
Date: 2015-05-14 14:21:35

Hi Jason,

On May 08 2015 or thereabouts, Jason Gerecke wrote:
quoted hunk ↗ jump to hunk
If we get an -EAGAIN error within either of the wacom_{get,set}_report
functions, we should use one of our retries if available. Also, log an error
if the functions fail so that we can be aware of what's going on.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
---
 drivers/hid/wacom_sys.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 7abf52c..3cd74d9 100644
--- 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 == -EPIPE || retval == -EAGAIN) && --retries);
I am not sure we should retry if the error is different than -EAGAIN.
TIMEDOUT might be possible but IMO, EPIPE means there is something wrong
and the retry will likely fail too.
+
+	if (retval < 0)
+		dev_err(&hdev->dev, "wacom_get_report: ran out of retries "
nitpick but you could use "hid_err(hdev" instead of a plain dev_err.
quoted hunk ↗ jump to hunk
+			"(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 == -EPIPE || retval == -EAGAIN) && --retries);
+
+	if (retval < 0)
+		dev_err(&hdev->dev, "wacom_set_report: ran out of retries "
+			"(last error = %d)\n", retval);
dito

Cheers,
Benjamin
 
 	return retval;
 }
-- 
2.4.0
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