How to make sure touchpad doesn't use psmouse.ko?

How to make sure touchpad doesn't use psmouse.ko?

[Kai-Heng Feng]

Hi,

When we are enabling a new hardware, sometimes touchpad may still use psmouse.ko due to bugs or missing IDs.
Is there a way to quickly to determine the touchpad doesn't use psmouse but something like SMBus or HID over I2C?

Kai-Heng

Re: How to make sure touchpad doesn't use psmouse.ko?

[Benjamin Tissoires]

Hi Kai-Heng,

On Mon, Oct 7, 2019 at 9:45 AM Kai-Heng Feng
<kai.heng.feng@canonical.com> wrote:
>
> Hi,
>
> When we are enabling a new hardware, sometimes touchpad may still use psmouse.ko due to bugs or missing IDs.
> Is there a way to quickly to determine the touchpad doesn't use psmouse but something like SMBus or HID over I2C?

Quick answer: no :)

For HID over I2C devices, they have to be included in the DSDT, so we
can detect those at the ACPI level, and they should automatically bind
to i2c-hid, if the dependencies are in place (available I2C adapter
and correct IRQ driver/binding).
The problem we have here is that we can not unbind the psmouse.ko
binding because we can not make the connection between the 2 bindings
from a HID or PS/2 point of view. They appear as 2 distinct mice.

For SMBus devices, currently only Synaptics and Elan have a SMBus
binding. And this is vendor specific to know if the SMBus binding will
be available and working.
In the Windows world, they do not have this question: every laptop
ships its own touchpad driver that has this information hardcoded or
put in the ini file.

Hope that this helps.

Cheers,
Benjamin

Re: How to make sure touchpad doesn't use psmouse.ko?

[Kai-Heng Feng]

Hi Benjamin,

> On Oct 11, 2019, at 17:35, Benjamin Tissoires <benjamin.tissoires@redhat.com> wrote:
> 
> Hi Kai-Heng,
> 
> On Mon, Oct 7, 2019 at 9:45 AM Kai-Heng Feng
> <kai.heng.feng@canonical.com> wrote:
>> 
>> Hi,
>> 
>> When we are enabling a new hardware, sometimes touchpad may still use psmouse.ko due to bugs or missing IDs.
>> Is there a way to quickly to determine the touchpad doesn't use psmouse but something like SMBus or HID over I2C?
> 
> Quick answer: no :)
> 
> For HID over I2C devices, they have to be included in the DSDT, so we
> can detect those at the ACPI level, and they should automatically bind
> to i2c-hid, if the dependencies are in place (available I2C adapter
> and correct IRQ driver/binding).
> The problem we have here is that we can not unbind the psmouse.ko
> binding because we can not make the connection between the 2 bindings
> from a HID or PS/2 point of view. They appear as 2 distinct mice.
> 
> For SMBus devices, currently only Synaptics and Elan have a SMBus
> binding. And this is vendor specific to know if the SMBus binding will
> be available and working.
> In the Windows world, they do not have this question: every laptop
> ships its own touchpad driver that has this information hardcoded or
> put in the ini file.
> 
> Hope that this helps.

Thanks for the answer. 
It means this scenario cannot be automatically tested.
It's unfortunate but I think doing a manual `modprobe -r psmouse` can still achieve what we want here.

Kai-Heng

> 
> Cheers,
> Benjamin
>