Re: [PATCH v2] HID: multitouch: Fetch feature reports on demand for Win8 devices

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Thu, Oct 08, 2015 at 06:10:23PM -0700, Andrew Duggan wrote:
> No, this touchpad doesn't have HID_QUIRK_NO_INIT_REPORTS set and
> usbhid/hid-core.c is calling usbhid_init_reports() which is retrieving
> feature 8. But, I did some additional testing and I wasn't able to reproduce
> this issue on other systems. The failure occurs on a Dell XPS 13 9343, but
> the exact same touchpad and the exact same kernel (I booted both systems off
> an external HD to ensure that the kernel and OS are identical) I didn't see
> a problem. I also tried a different USB PTP touchpad which didn't have an
> issue. Also, I tried returning in mt_get_feature() instead of reading the
> report when the report id is 8. When I did that everything worked.
> 
> So as of right now, it looks like a single non production USB PTP touchpad
> fails on one particular system. But, all other tests have been successful.
> 
> Let me know if you have any other suggestions for me to test. But, it seems
> like this failure might be fairly isolated.

Thanks a lot for testing all this.

If the failure is limited to a single non-production touchpad then, I
suppose we should be fine. As long as there are no such systems out
there in the wild.

One additional thing we could check in mt_get_feature() is if the device
is connected via I2C and only in that case fetch the feature in
question.

Jiri, Benjamin, what do you think?