Re: [PATCH RESEND] Input: ALPS - Fix two-finger scroll breakage in right side on ALPS touchpad

From: Takashi Iwai
Date: Fri Aug 25 2017 - 04:37:41 EST


On Fri, 25 Aug 2017 01:09:55 +0200,
Dmitry Torokhov wrote:
>
> Hi Takashi,
>
> On Tue, Aug 22, 2017 at 10:17:00PM +0200, Takashi Iwai wrote:
> > From: Masaki Ota <masaki.ota@xxxxxxxxxxx>
> >
> > Fixed the issue that two finger scroll does not work correctly
> > on V8 protocol. The cause is that V8 protocol X-coordinate decode
> > is wrong at SS4 PLUS device. I added SS4 PLUS X decode definition.
> >
> > Mote notes:
> > the problem manifests itself by the commit e7348396c6d5 ("Input: ALPS
> > - fix V8+ protocol handling (73 03 28)"), where a fix for the V8+
> > protocol was applied. Although the culprit must have been present
> > beforehand, the two-finger scroll worked casually even with the
> > wrongly reported values by some reason. It got broken by the commit
> > above just because it changed x_max value, and this made libinput
> > correctly figuring the MT events. Since the X coord is reported as
> > falsely doubled, the events on the right-half side go outside the
> > boundary, thus they are no longer handled. This resulted as a broken
> > two-finger scroll.
> >
> > One finger event is decoded differently, and it didn't suffer from
> > this problem. The problem was only about MT events. --tiwai
> >
> > Fixes: e7348396c6d5 ("Input: ALPS - fix V8+ protocol handling (73 03 28)")
> > Signed-off-by: Masaki Ota <masaki.ota@xxxxxxxxxxx>
> > Tested-by: Takashi Iwai <tiwai@xxxxxxx>
> > Tested-by: Paul Donohue <linux-kernel@xxxxxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> > ---
> >
> > Dmitry, I resend this patch from Ota-san, as the previous thread was
> > cursed. Since this is an annoying regression in the recent kernels,
> > could you apply this? Thanks!
>
> Sorry I checked out on this patch for a bit. It is now applied and I
> will send it Linuswards in the next day or two.
>
> Thanks!

Great, thanks!


Takashi