Re: Touchpad stickiness on AMD laptops (was Dell Inspiron/XPS)

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On Tue, Jan 11, 2022 at 11:34 AM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
> Hi Wolfram,
>
> On 1/6/22 14:14, Wolfram Sang wrote:
> > Hi Hans,
> >
> > bumping this old thread because there might be some progress and it
> > still affects quite some people.
> >
> >> But I must be honest here, I don't see much progress being made
> >> on this until someone with a significant amount of kernel / hw-enablement
> >> experience gets it hands on one of these models. Either because some
> >
> > So, I am quite optimistic that Andrea's issue is the same one which
> > Miroslav Bendik dived into [1]. I will surely try to help with part of
> > the PIIX I2C driver, but I lack the experience with the RMI4 driver. I
> > wonder if you could have a look and maybe share your thoughts?
> >
> > Thanks and all the best,
> >
> >    Wolfram
> >
> > [1] https://lore.kernel.org/r/CAPoEpV0ZSidL6aMXvB6LN1uS-3CUHS4ggT8RwFgmkzzCiYJ-XQ@xxxxxxxxxxxxxx
>
> Benjamin Tissoires really is the export on the synaptics PS/2 -> switch to
> smbus mode devices, he did all the initial hw-enablement for them.
>
> Benjamin, see the email Wolfram linked above. It seems that on AMD
> laptops we have synaptics intertouch devices connected to a plain
> PIIX4 compatible I2C controller.

Oh, nice (looking at the thread). IIRC last time somebody tried to
communicate with those touchpads it wasn't working at all.

>
> So we need to either add support for SMBUS host-notify to the
> PIIX4 smbus driver (at least for AMD parts) or we need to support
> OOB IRQ signalling in the rmi4 code, assuming there is an OOB IRQ
> at all.

If the touchpad is using SMBus, we need to have Host Notify. Google
gave me the following datasheet for PIIX4
https://www.intel.com/Assets/PDF/datasheet/290562.pdf and it seems we
would need to enable something in the section 7.3.9.

However, without the hardware it's going to be tough for me to enable :/

For regular I2C touchpads, there is an OOB IRQ we can set up, but when
the devices are presented and enabled through PS/2 first, they are
using SMBus only AFAICT.

Cheers,
Benjamin

>
> I've also added Mario Limonciello from AMD's client group to the Cc,
>
> Mario, we can really use some help / insight from AMD here, both with
> the problem to detect the IO addresses of the AMD PIIX4 compatible
> smbus controller as well as with smbus host-notify support, see:
>
> https://lore.kernel.org/r/CAPoEpV0ZSidL6aMXvB6LN1uS-3CUHS4ggT8RwFgmkzzCiYJ-XQ@xxxxxxxxxxxxxx
>
> Regards,
>
> Hans
>




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