linux-kernel - Re: [PATCH 2/2] hid-ntrig: init settle and mode check

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Date:	Fri, 11 Mar 2011 11:52:38 +1000
From:	Peter Hutterer <peter.hutterer@...-t.net>
To:	Rafi Rubin <rafi@...s.upenn.edu>
Cc:	jkosina@...e.cz, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org, micki@...rig.com,
	rydberg@...omail.se, chatty@...c.fr
Subject: Re: [PATCH 2/2] hid-ntrig: init settle and mode check

On Wed, Mar 09, 2011 at 11:33:52PM -0500, Rafi Rubin wrote:
> Adding a wait before the wakeup signal.
> 
> As a precautionary measure sanity check the current sensor mode.  If
> needed reset it to "dual".
> 
> Signed-off-by: Rafi Rubin <rafi@...s.upenn.edu>
> 
> When the device is responding poorly and needs the wakeup call, it was
> missing it.  Giving it a chance to settle first improves the chances
> that signal gets through.
> 
> I was also seeing the device come up in strange modes where it did not
> respond to physical stimulus.  Hopefully the quirk will fix that, but
> even so it seems like a good idea to check.  It also makes me curious
> what the "off" code is.
> ---
>  drivers/hid/hid-ntrig.c |   45 +++++++++++++++++++++++++++++++++++++++++++--
>  1 files changed, 43 insertions(+), 2 deletions(-)

no negative effects

Tested-by: Peter Hutterer <peter.hutterer@...-t.net>

Cheers,
  Peter
> 
> diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
> index 850ba14..fa862c5 100644
> --- a/drivers/hid/hid-ntrig.c
> +++ b/drivers/hid/hid-ntrig.c
> @@ -110,6 +110,36 @@ static int ntrig_version_string(unsigned char *raw, char *buf)
>  	return sprintf(buf, "%u.%u.%u.%u.%u", a, b, c, d, e);
>  }
>  
> +static inline int ntrig_get_mode(struct hid_device *hdev)
> +{
> +	struct hid_report *report = hdev->report_enum[HID_FEATURE_REPORT].
> +				    report_id_hash[0x0d];
> +
> +	if (!report)
> +		return -EINVAL;
> +
> +	usbhid_submit_report(hdev, report, USB_DIR_IN);
> +	usbhid_wait_io(hdev);
> +	return (int)report->field[0]->value[0];
> +}
> +
> +static inline void ntrig_set_mode(struct hid_device *hdev, const int mode)
> +{
> +	struct hid_report *report;
> +	__u8 mode_commands[4] = { 0xe, 0xf, 0x1b, 0x10 };
> +
> +	if (mode < 0 || mode > 3)
> +		return;
> +
> +	report = hdev->report_enum[HID_FEATURE_REPORT].
> +		 report_id_hash[mode_commands[mode]];
> +
> +	if (!report)
> +		return;
> +
> +	usbhid_submit_report(hdev, report, USB_DIR_IN);
> +}
> +
>  static void ntrig_report_version(struct hid_device *hdev)
>  {
>  	int ret;
> @@ -905,8 +935,19 @@ static int ntrig_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  
>  	/* This is needed for devices with more recent firmware versions */
>  	report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0x0a];
> -	if (report)
> -		usbhid_submit_report(hdev, report, USB_DIR_OUT);
> +	if (report) {
> +		/* Let the device settle to ensure the wakeup message gets
> +		 * through */
> +		usbhid_wait_io(hdev);
> +		usbhid_submit_report(hdev, report, USB_DIR_IN);
> +
> +		/*
> +		 * Sanity check: if the current mode is invalid reset it to
> +		 * something reasonable.
> +		 */
> +		if (ntrig_get_mode(hdev) >= 4)
> +			ntrig_set_mode(hdev, 3);
> +	}
>  
>  	ntrig_report_version(hdev);
>  
> -- 
> 1.7.4.1
> 
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