linux-kernel - RE: [PATCH] Input: elan_i2c - add ASUS EeeBook X205TA special touchpad fw

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Date:   Wed, 8 Mar 2017 14:30:42 +0800
From:   廖崇榮 <kt.liao@....com.tw>
To:     'Matjaž Hegedič' <matjaz.hegedic@...il.com>,
        "'Dmitry Torokhov'" <dmitry.torokhov@...il.com>
Cc:     <linux-input@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        '黃世鵬 經理' <phoenix@....com.tw>,
        <miller_wang@....com.tw>
Subject: RE: [PATCH] Input: elan_i2c - add ASUS EeeBook X205TA special touchpad fw

Hi Matjaz,

-----Original Message-----
From: Matjaž Hegedič [mailto:matjaz.hegedic@...il.com] 
Sent: Tuesday, March 07, 2017 6:52 PM
To: 廖崇榮; 'Dmitry Torokhov'
Cc: linux-input@...r.kernel.org; linux-kernel@...r.kernel.org; 黃世鵬 經理; miller_wang@....com.tw
Subject: Re: [PATCH] Input: elan_i2c - add ASUS EeeBook X205TA special touchpad fw

Hi Dmitry, KT!

On 2017-03-07 08:05, 廖崇榮 wrote:
> Hi Dmitry
>
> -----Original Message-----
> From: Dmitry Torokhov [mailto:dmitry.torokhov@...il.com]
> Sent: Tuesday, March 07, 2017 3:55 AM
> To: KT Liao
> Cc: linux-input@...r.kernel.org; linux-kernel@...r.kernel.org; Matjaz 
> Hegedic
> Subject: Re: [PATCH] Input: elan_i2c - add ASUS EeeBook X205TA special 
> touchpad fw
>
> On Sun, Mar 05, 2017 at 03:13:02AM +0100, Matjaz Hegedic wrote:
>> EeeBook X205TA is yet another ASUS device with a special touchpad 
>> firmware that needs to be accounted for during initialization, or 
>> else the touchpad will go into an invalid state upon suspend/resume.
>> Adding the appropriate ic_type and product_id check fixes the problem.
>
> KT, does this look reasonable? Are there more ASUS models that need 
> such handling?
> [KT] : I just discuss it with FW team.
> We can't confirm it right now because it's an old product. And the 
> solution focus on power-on issue, not suspend/resume.
> I will let you know once we figure it out.
>
> Our FW has modified, the issue should not happen on new models.
>
> Thanks		KT

As it is now, the touchpad will stop working upon resume, returning an invalid id (and requires a cumbersome workaround of reloading the module). As the touchpad FW is opaque to me, the only way I could resolve the bug was through trial-and-error. Including the touchpad in the 'special fw' resolves the bug and the touchpad resumes without issue.

Now, even if the function is indeed used to resolve a different issue on other ASUS touchpads, I would argue that this is the most pragmatic way of resolving the problem on X205TA, X205TAW and F205TA (and possibly also X200HA & X206HA, though I don't have those to test).

It shouldn't affect any other models or touchpad products.

Thanks!

I agree your opinion.
The special handle simply changes the sequence of commands and adds delay cycle. 
It is harmless to general Elan products but rescue control flaws in some FW.

Thanks		KT
>>
>> Signed-off-by: Matjaz Hegedic <matjaz.hegedic@...il.com>
>> ---
>>  drivers/input/mouse/elan_i2c_core.c | 22 ++++++++++++----------
>>  1 file changed, 12 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/input/mouse/elan_i2c_core.c
>> b/drivers/input/mouse/elan_i2c_core.c
>> index 2c7d287..dde3ad7 100644
>> --- a/drivers/input/mouse/elan_i2c_core.c
>> +++ b/drivers/input/mouse/elan_i2c_core.c
>> @@ -218,17 +218,19 @@ static int elan_query_product(struct 
>> elan_tp_data *data)
>>
>>  static int elan_check_ASUS_special_fw(struct elan_tp_data *data)  {
>> -	if (data->ic_type != 0x0E)
>> -		return false;
>> -
>> -	switch (data->product_id) {
>> -	case 0x05 ... 0x07:
>> -	case 0x09:
>> -	case 0x13:
>> -		return true;
>> -	default:
>> -		return false;
>> +	if (data->ic_type == 0x0E) {
>> +		switch (data->product_id) {
>> +		case 0x05 ... 0x07:
>> +		case 0x09:
>> +		case 0x13:
>> +			return true;
>> +		}
>>  	}
>> +	/* ASUS EeeBook X205TA */
>> +	else if (data->ic_type == 0x8 && data->product_id == 0x26)
>> +		return true;
>> +
>> +	return false;
>>  }
>>
>>  static int __elan_initialize(struct elan_tp_data *data)
>> --
>> 2.7.4
>>
>
> Thanks.
>