Re: [REGRESSION] Right touchpad button disabled on Dell 7750

Takashi Iwai
2022-03-18T13:11:50Z

On Fri, 18 Mar 2022 14:07:40 +0100,
José Expósito wrote:
>
> Hi Takashi,
>
> Thanks for reporting the regression here.
>
> On Fri, Mar 18, 2022 at 12:42:31PM +0100, Takashi Iwai wrote:
> > Hi,
> >
> > we received a bug report about the regression of the touchpad on Dell
> > 7750 laptop, the right touchpad button is disabled on recent kernels:
> > https://bugzilla.suse.com/show_bug.cgi?id=1197243
> >
> > Note that it's a physical button, not a virtual clickpad button.
> >
> > The regression seems introduced by the upstream commit
> > 37ef4c19b4c659926ce65a7ac709ceaefb211c40 ("Input: clear
> > BTN_RIGHT/MIDDLE on buttonpads") that was backported to stable 5.16.x
> > kernel.
> >
> > The device is managed by hid-multitouch driver, and the further
> > investigation revealed that it's rather an incorrectly recognized
> > buttonpad property; namely, ID_DG_BUTTONTYPE reports it being 0 =
> > clickable touchpad although it's not. I built a test kernel to ignore
> > this check and it was confirmed to make the right button working again
> > by the reporter.
> >
> > Is this check really correct in general? Or do we need some
> > device-specific quirk?
>
> A couple of days ago another user with the same laptop (Dell Precision
> 7550 or 7750) emailed me to report the issue and I sent him a patch for
> testing.
>
> I he confirms that the patch works, I'll send it to the mailing list.
>
> I believe that your analysis of the regression is correct and I think
> that we'd need to add a quirk for the device.
>
> In case you want to have a look to the patch, I added it to this
> libinput [1] report.

Great, I'll try to build and ask the reporter to test with the patch.

Thanks!

Takashi
>
> Thanks,
> Jose
>
> [1] https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/726#note_1303623
>