Thread (2 messages) 2 messages, 2 authors, 2013-01-24

[PATCH] Input: wacom - fix wacom_set_report retry logic

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STALE5015d

From: <hidden>
Date: 2013-01-24 01:52:45
Subsystem: input (keyboard, mouse, joystick, touchscreen) drivers, the rest · Maintainers: Dmitry Torokhov, Linus Torvalds

From: Chris Bagwell <redacted>

Logic sets a value and then reads it back to make sure it worked
and retries write on failures.  Since read and write share a buffer,
it needs to be set back up before writing though.

Issue is not seen a lot because 1) it doesn't need to retry for
a lot of tablets and 2) a lot of failures that need a retry are
from an -ETIMEDOUT and hopefully buffer is not touched in this case.

At least one user has shown logs with buffer being modified during
-ETIMEDOUT case with linux 3.7 kernel.

Signed-off-by: Chris Bagwell <redacted>
---
 drivers/input/tablet/wacom_sys.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/input/tablet/wacom_sys.c b/drivers/input/tablet/wacom_sys.c
index f92d34f..aaf23ae 100644
--- a/drivers/input/tablet/wacom_sys.c
+++ b/drivers/input/tablet/wacom_sys.c
@@ -553,10 +553,10 @@ static int wacom_set_device_mode(struct usb_interface *intf, int report_id, int
 	if (!rep_data)
 		return error;
 
-	rep_data[0] = report_id;
-	rep_data[1] = mode;
-
 	do {
+		rep_data[0] = report_id;
+		rep_data[1] = mode;
+
 		error = wacom_set_report(intf, WAC_HID_FEATURE_REPORT,
 		                         report_id, rep_data, length, 1);
 		if (error >= 0)
-- 
1.8.1
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