linux-kernel - Re: [PATCH 2/3] HID: Implement Wacom quirk in the kernel

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Date:	Wed, 3 Feb 2010 15:50:29 +0100 (CET)
From:	Jiri Kosina <jkosina@...e.cz>
To:	Ping Cheng <pinglinux@...il.com>
Cc:	"Gunn, Brian" <bgunn@...ekai.com>,
	Marcel Holtmann <marcel@...tmann.org>,
	linux-kernel@...r.kernel.org,
	BlueZ development <linux-bluetooth@...r.kernel.org>
Subject: Re: [PATCH 2/3] HID: Implement Wacom quirk in the kernel

On Fri, 29 Jan 2010, Ping Cheng wrote:

>       +       rep_data[0] = 0x03; rep_data[1] = 0x00;
>       +       limit =3;
>       +       do {
>       +               ret = hdev->hid_output_raw_report(hdev, rep_data, 2,
>       +                               HID_FEATURE_REPORT);
>       +       } while (ret < 0 && limit-- > 0);
> 
>  
> hdev->hid_output_raw_report error is not a hard failure, i.e., the following four lines are unnecessay. We can continue with the
> rest of the code.
>  
>       +       if (ret < 0) {
>       +               dev_err(&hdev->dev, "failed to poke device #1, %d\n", ret);
>       +               goto err_free;
>       +       }
>       +
>       +       /* 0x06 - high reporting speed, 0x05 - low speed */
>       +       rep_data[0] = 0x06; rep_data[1] = 0x00;
>       +       limit = 3;
>       +       do {
>       +               ret = hdev->hid_output_raw_report(hdev, rep_data, 2,
>       +                               HID_FEATURE_REPORT);
>       +       } while (ret < 0 && limit-- > 0);
> 
>  
> Same comments apply here. "/* Note that if query fails it is not a hard failure */" is the comments we use in the corresponding
> Wacom USB driver, wacom_sys.c

Thanks for the feedback. I have queued the patch below on top of all the 
other changes.


From: Jiri Kosina <jkosina@...e.cz>
Subject: [PATCH] HID: make Wacom modesetting failures non-fatal

With Wacom tablet mode-setting moved from userspace into kernel,
we don't have to consider failures of device queries through the
_raw callback as hard failure, as the driver can safely continue
anyway.

This is consistent with the current USB driver in wacom_sys.c

Reported-by: Ping Cheng <pinglinux@...il.com>
Signed-off-by: Jiri Kosina <jkosina@...e.cz>
---
 drivers/hid/hid-wacom.c |   17 +++++++++--------
 1 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/hid/hid-wacom.c b/drivers/hid/hid-wacom.c
index b8778db..8d3b46f 100644
--- a/drivers/hid/hid-wacom.c
+++ b/drivers/hid/hid-wacom.c
@@ -181,6 +181,11 @@ static int wacom_probe(struct hid_device *hdev,
 		goto err_free;
 	}
 
+	/*
+	 * Note that if the raw queries fail, it's not a hard failure and it
+	 * is safe to continue
+	 */
+
 	/* Set Wacom mode2 */
 	rep_data[0] = 0x03; rep_data[1] = 0x00;
 	limit = 3;
@@ -188,10 +193,8 @@ static int wacom_probe(struct hid_device *hdev,
 		ret = hdev->hid_output_raw_report(hdev, rep_data, 2,
 				HID_FEATURE_REPORT);
 	} while (ret < 0 && limit-- > 0);
-	if (ret < 0) {
-		dev_err(&hdev->dev, "failed to poke device #1, %d\n", ret);
-		goto err_free;
-	}
+	if (ret < 0)
+		dev_warn(&hdev->dev, "failed to poke device #1, %d\n", ret);
 
 	/* 0x06 - high reporting speed, 0x05 - low speed */
 	rep_data[0] = 0x06; rep_data[1] = 0x00;
@@ -200,10 +203,8 @@ static int wacom_probe(struct hid_device *hdev,
 		ret = hdev->hid_output_raw_report(hdev, rep_data, 2,
 				HID_FEATURE_REPORT);
 	} while (ret < 0 && limit-- > 0);
-	if (ret < 0) {
-		dev_err(&hdev->dev, "failed to poke device #2, %d\n", ret);
-		goto err_free;
-	}
+	if (ret < 0)
+		dev_warn(&hdev->dev, "failed to poke device #2, %d\n", ret);
 
 	hidinput = list_entry(hdev->inputs.next, struct hid_input, list);
 	input = hidinput->input;
-- 
1.6.4.2

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