Re: v4.1 to v4.7: regression in tsc2005 driver

Pali Rohár
2016-07-20T16:33:15Z

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On Wednesday 20 July 2016 02:53:07 Dmitry Torokhov wrote:
> On Tue, Jul 19, 2016 at 07:39:08PM -0500, Michael Welling wrote:
> > On Tue, Jul 19, 2016 at 04:51:20PM -0700, Dmitry Torokhov wrote:
> > > On Sun, Jul 17, 2016 at 05:56:36PM -0500, Michael Welling wrote:
> > > > On Sun, Jul 17, 2016 at 10:03:39PM +0200, Pavel Machek wrote:
> > > > > On Sun 2016-07-17 13:51:34, Michael Welling wrote:
> > > > > > On Sun, Jul 17, 2016 at 08:42:09PM +0200, Pavel Machek
> > > > > > wrote:
> > > > > > > On Sun 2016-07-17 13:24:45, Michael Welling wrote:
> > > > > > > > On Sun, Jul 17, 2016 at 07:52:57PM +0200, Pavel Machek
> > > > > > > > wrote:
> > > > > > > > > Hi!
> > > > > > > > >
> > > > > > > > > tsc2005 driver changed input device name, from
> > > > > > > > >
> > > > > > > > > drivers/input/touchscreen/tsc2005.c:
> > > > > > > > > input_dev->name = "TSC2005 touchscreen";
> > > > > > > > >
> > > > > > > > > to "TSC200X touchscreen". Unfortunately, X seems to
> > > > > > > > > propagate that name to userspace, where it is needed
> > > > > > > > > to be able to do
> > >
> > > Technically X _is_ userspace.
> > >
> > > > > > > > > xinput --set-prop --type=int ...
> > > > > > > > >
> > > > > > > > > with the right arguments to calibrate touchscreen.
> > > > > > > > > (Touchscreen is unusable without calibration).
> > > > > > > > >
> > > > > > > > > What to do with that?
> > >
> > > Hmm, I do not think we ever committed for the device names to be
> > > stable. You are supposed to locate touchscreen device based on
> > > its properties and you might need some heuristic if you
> > > encounter a system with more than one such touchscreen.
> > >
> > > > > > > > The input_dev name could be passed to the common probe
> > > > > > > > function.
> > > > > > > >
> > > > > > > > http://lxr.free-electrons.com/source/drivers/input/touc
> > > > > > > > hscreen/tsc2005.c#L65
> > > > > > >
> > > > > > > That would be preffered, I guess.
> > > > > > >
> > > > > > > How many stable releases are affected?
> > > > > >
> > > > > > Well this patch is 9 months old now. Lets see.
> > > > > >
> > > > > > It was introduced in v4.4-rc1. So v4.4, v4.5 and v4.6.
> > > > >
> > > > > Ok, thanks for the information. I believe changing it back to
> > > > > "TSC2005" version makes sense (and then fixing it in stable).
> > >
> > > Do we know how many users are affected?
> >
> > Anyone with an old N900 and the smarts to update the kernel.
>
> Soo... only Pavel? ;)

No, more are playing with upstream kernel and N900. Now I see that Maemo
applications looks also for string "TSC2005 touchscreen"...

I'm also for changing name back to "TSC2005 touchscreen" for TSC2005
touchscreen.

--
Pali Rohár
pali.rohar@gmail.com

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