RE: elan_i2c trackpad on T480s not reporting as clickpad

[廖崇榮 <kt.liao@xxxxxxxxxx>]

Hi Dmitry,

-----Original Message-----
From: Dmitry Torokhov [mailto:dmitry.torokhov@xxxxxxxxx] 
Sent: Friday, September 14, 2018 2:47 AM
To: 廖崇榮
Cc: angelsl@xxxxxxx; linux-input@xxxxxxxxxxxxxxx
Subject: Re: elan_i2c trackpad on T480s not reporting as clickpad

Hi KT,

On Thu, Sep 13, 2018 at 2:49 AM 廖崇榮 <kt.liao@xxxxxxxxxx> wrote:
>
> Hi Hao Wei,
>
> Sorry for later reply.
>
> I check with FW team, Smbus won’t support information fetch in recent trackpad.
> I ever discuss this issue with Linux pro and tell them that all 
> information should be fetched by PS/2 bus SMbus only for report data

Is this true for a particular firmware version, or for all future firmwares from Elan? What about firmware flash procedure that implemented in elan_i2c_smbus? Can you enumerate exactly what data should be fetched via PS/2 access versus SMbus?

I must say it is unfortunately that we are introducing even more dependencies on PS/2 here...

Our fw team has removed SMBus command from last year if device's flash size is not sufficient.
Some FW just removed function and keep SMBus communication. It cause no error in SMbus but fetch the wrong information.

We suggest all information should be fetched from PS/2 and SMbus just handle hello package and 32bytes report.

I never try FW update by SMbus, I will try it once I find a test platform.


>
> I will check if the fixed patch upaload.
>
> B.R
> KT
>
> -----Original Message-----
> From: Hao Wei Tee [mailto:angelsl@xxxxxxx]
> Sent: Thursday, September 06, 2018 4:01 PM
> To: linux-input@xxxxxxxxxxxxxxx
> Cc: 廖崇榮
> Subject: elan_i2c trackpad on T480s not reporting as clickpad
>
> Hi,
>
> I have a Lenovo T480s with an Elantech one-button trackpad (aka clickpad) but for some reason the kernel is not reporting it as a clickpad.
>
> It appears that the module checks the SM version for a bit and reports it as a clickpad if the bit is set, but my trackpad is reporting a SM version of 0, so the flag on L184 here[1] is false.
>
> [1]: 
> https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git/tree/dr
> ivers/input/mouse/elan_i2c_smbus.c#n168
>
> I am wondering if there is some other flag in some other field that may indicate this is a clickpad.
>
> Here is the other information reported by the trackpad:
>
>      elan_i2c 6-0015: Elan Touchpad: Module ID: 0x0020, Firmware: 0x0001, Sample: 0x0000, IAP: 0x0000
>      elan_i2c 6-0015: Elan Touchpad Extra Information:
>                          Max ABS X,Y:   3052,1888
>                          Width X,Y:   127,125
>                          Resolution X,Y:   31,31 (dots/mm)
>                          ic type: 0x20
>                          info pattern: 0x0
>
> This crude patch setting `clickpad = 1` works fine on my T480s. I'm pretty sure there is some way to actually check for a clickpad instead of special-casing this particular module/product ID.
>
> diff --git a/elan_i2c_core.c b/elan_i2c_core.c index f5ae248..718cb19 
> 100644
> --- a/elan_i2c_core.c
> +++ b/elan_i2c_core.c
> @@ -241,6 +241,16 @@ static int elan_check_ASUS_special_fw(struct elan_tp_data *data)
>         return false;
>   }
>
> +static void elan_check_clickpad(struct elan_tp_data *data) {
> +       if (data->ic_type == 0x20
> +               && data->product_id == 0x20
> +               && data->sm_version == 0) {
> +               data->clickpad = 1;
> +       }
> +       return;
> +}
> +
>   static int __elan_initialize(struct elan_tp_data *data)
>   {
>         struct i2c_client *client = data->client; @@ -257,6 +267,8 @@ static int __elan_initialize(struct elan_tp_data *data)
>         if (error)
>                 return error;
>
> +       elan_check_clickpad(data);
> +
>         /*
>          * Some ASUS devices were shipped with firmware that requires
>          * touchpads to be woken up first, before attempting to switch
> --
>
> Has anyone else run into this issue, or does anyone know anything about this?
>
> Thanks.
>
> --
> Hao Wei
>

Thanks.

--
Dmitry