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Date: Thu, 18 Aug 2011 11:07:23 +0800
From: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reply-To: gaowanlong@cn.fujitsu.com
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To: JJ Ding <jj_ding@emc.com.tw>
CC: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        Seth Forshee <seth.forshee@canonical.com>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Aaron Huang <aaron_huang@emc.com.tw>, Tom Lin <tom_lin@emc.com.tw>,
        Eric Piel <E.A.B.Piel@tudelft.nl>, Daniel Kurtz <djkurtz@chromium.org>,
        Chase Douglas <chase.douglas@canonical.com>,
        Henrik Rydberg <rydberg@euromail.se>,
        Alessandro Rubini <rubini@cvml.unipv.it>
Subject: Re: [PATCH 4/6] Input: elantech - work around EC buffer
References: <1313632629-23603-1-git-send-email-jj_ding@emc.com.tw> <1313632629-23603-5-git-send-email-jj_ding@emc.com.tw>
In-Reply-To: <1313632629-23603-5-git-send-email-jj_ding@emc.com.tw>
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On 08/18/2011 09:57 AM, JJ Ding wrote:
> With some EC chips, when we resync due to bad packets, those bad bytes would
> still remain in EC's buffer area. That makes us always get bad data back,
> no matter what.
>
> So shift packet for 1 byte when encounter bad packet, until we get rid of those
> bytes.
>
> Signed-off-by: JJ Ding<jj_ding@emc.com.tw>
> ---
>   drivers/input/mouse/elantech.c |    9 +++++++--
>   1 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
> index 032181c..7b9b6e5 100644
> --- a/drivers/input/mouse/elantech.c
> +++ b/drivers/input/mouse/elantech.c
> @@ -411,20 +411,25 @@ static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
>   	switch (etd->hw_version) {
>   	case 1:
>   		if (etd->paritycheck&&  !elantech_check_parity_v1(psmouse))
> -			return PSMOUSE_BAD_DATA;
> +			goto bad_packet;
>
>   		elantech_report_absolute_v1(psmouse);
>   		break;
>
>   	case 2:
>   		if (etd->paritycheck&&  !packet_simple_check_v2(psmouse))
> -			return PSMOUSE_BAD_DATA;
> +			goto bad_packet;
>
>   		elantech_report_absolute_v2(psmouse);
>   		break;
>   	}
>
>   	return PSMOUSE_FULL_PACKET;
> +
> + bad_packet:
You may introduce space here.
> +	memmove(psmouse->packet, psmouse->packet + 1, psmouse->pktsize - 1);
> +	psmouse->pktcnt--;
> +	return PSMOUSE_GOOD_DATA;
>   }
>
>   /*


-- 
Thanks
Wanlong Gao