diff mbox

Input: wacom - fix wacom_set_report retry logic

Message ID 1358992356-7898-1-git-send-email-chris@cnpbagwell.com (mailing list archive)
State New, archived
Headers show

Commit Message

chris@cnpbagwell.com Jan. 24, 2013, 1:52 a.m. UTC 
From: Chris Bagwell <chris@cnpbagwell.com>

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 <chris@cnpbagwell.com>
---
 drivers/input/tablet/wacom_sys.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Dmitry Torokhov Jan. 24, 2013, 3:38 a.m. UTC | #1 
On Wed, Jan 23, 2013 at 07:52:36PM -0600, chris@cnpbagwell.com wrote:
> From: Chris Bagwell <chris@cnpbagwell.com>
> 
> 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 <chris@cnpbagwell.com>

Applied, thank you Chris. 

> ---
>  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
>
diff mbox

Patch

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)