linux-kernel - Re: [PATCH v2] input: mouse: add qci touchpad driver

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Message-ID: <4C756049.2090408@codeaurora.org>
Date:	Wed, 25 Aug 2010 14:26:17 -0400
From:	Neil Leeder <nleeder@...eaurora.org>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:	Stepan Moskovchenko <stepanm@...eaurora.org>,
	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Horace Fu <horace.fu@...ntatw.com>,
	Mandeep Singh Baines <msb@...omium.org>,
	Trilok Soni <tsoni@...eaurora.org>
Subject: Re: [PATCH v2] input: mouse: add qci touchpad driver

On 8/19/2010 6:19 PM, Neil Leeder wrote:
> Hi Dmitry,
>
> On 8/19/2010 1:33 AM, Dmitry Torokhov wrote:
>> On Wed, Aug 18, 2010 at 05:38:38PM -0400, Neil Leeder wrote:
>>> Using proto=bare gets around the GETINFO failure, but doesn't help
>>> with the more important GETID failure.
>>
>> Does it help if you change write() to transmit (and read) 1 byte at a
>> time?
>>
>
> Thanks for the suggestions. Nothing I change seems able to get a
> consistent valid response to GETID. I think this is the first time
> anyone has written anything other than 0xF4 to the firmware in the EC
> and it's just not passing through the other PS/2 commands and responses
> reliably.
>
>> One way would be to look for PSMOUSE_CMD_ENABLE/PSMOUSE_CMD_DISABLE
>> (0xf4/0xf5) in ->write() method to switch between 1 and 3-byte transfers.
>
> If I force my way past GETID and set the receive length to 3 based on
> seeing F4/F5 being written then the touchpad does work. However the
> serio driver is now a touchpad-specific driver rather than a generic
> PS/2 one. I have a keyboard on the same device. I'm not sure if it will
> work with serio, but if so it will probably have its own requirements
> for the length of data sent on responses, probably not 3.
>
> BTW, using 1 as the receive length for commands has its own problems as
> some commands require more than one byte response (GETID, GETINFO). I
> can work around it, but it's not particularly clean and getting further
> away from a generic driver.
>
> At this point I'm thinking that the interface is close to being able to
> work with serio/psmouse, but just not close enough. The unreliability of
> responding to basic commands as well as the length of data problems
> indicates some custom driver is going to be needed. That could either be
> Quanta's original touchpad driver I posted, or a modification of your
> serio driver. I'd lean towards not having a serio driver which includes
> workarounds for a specific device, but I'd appreciate hearing your opinion.
>
> Thanks.

Hi Dmitry,

Any comment on the above alternatives?

A third suggestion might be to have a fairly general serio driver, and 
rewrite the original Quanta driver to use serio rather than using i2c 
directly. I think that has its own set of problems, but thought I'd 
mention it anyway. The nuvoTon EC doesn't present a fully-working and 
reliable PS/2 interface to the driver so I'd lean toward using the 
Quanta touchpad driver by itself.

Thanks.

--
Neil
-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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