Re: QUANTA touchscreen controller integrated in HP2310ti no longer recognised (regression in 3.5 and later as compared to 3.3)

[Simon Farnsworth <simon.farnsworth@onelan.co.uk>]

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On Tuesday 21 August 2012 21:06:26 Henrik Rydberg wrote:
> Hi Simon,
> 
> > We're going through our collection of touch screens, making sure that they all 
> > work with current kernels, and we've found one that doesn't work with today's 
> > Linus master.
> > 
> > lsusb describes the screen as:
> > Bus 006 Device 002: ID 0408:3001 Quanta Computer, Inc. Optical Touch Screen
> 
> What about 0408:3008, does that one work?
> 
I don't have a sample of 0408:3008 to try.

> > Any ideas on the best way to resolve this regression?
> 
> What does 'cat /sys/bus/hid/devices/0003:0408:3001.0001/modalias' say?

It's the same whether or not I revert the patch:

# cat /sys/bus/hid/devices/0003:0408:3001.0001/modalias
hid:b0003g0000v00000408p00003001

If I've understood hid-code.c correctly, this means that 
hdev->group == HID_GROUP_ANY, implying that neither hid_scan_usage nor 
hid_scan_report have run.

> 
> The patch below ought to be enough to make it work, although it is
> still unclear why it is needed.
> 
I'd like to get to the bottom of why this patch is needed - the patch I
reverted covered 71 touchscreen controllers, and the fact that hdev->group is
set to HID_GROUP_ANY worries me - I'm concerned that there's something
deeper wrong that's causing the USB HID core to not be able to get the report
descriptor reliably.

> Thanks,
> Henrik
> 
> ---
> 
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index bd4bc3c..2b775c3 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -963,7 +963,7 @@ static const struct hid_device_id mt_devices[] = {
>                 MT_USB_DEVICE(USB_VENDOR_ID_QUANTA,
>                         USB_DEVICE_ID_QUANTA_OPTICAL_TOUCH) },
>         { .driver_data = MT_CLS_CONFIDENCE_CONTACT_ID,
> -               MT_USB_DEVICE(USB_VENDOR_ID_QUANTA,
> +               HID_USB_DEVICE(USB_VENDOR_ID_QUANTA,
>                         USB_DEVICE_ID_QUANTA_OPTICAL_TOUCH_3001) },
>         { .driver_data = MT_CLS_CONFIDENCE_CONTACT_ID,
>                 MT_USB_DEVICE(USB_VENDOR_ID_QUANTA,
-- 
Simon Farnsworth
Software Engineer
ONELAN Ltd
http://www.onelan.com

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