Date:	Thu, 17 Dec 2015 18:28:09 +0100
From:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:	Nish Aravamudan <nish.aravamudan@...il.com>
Cc:	Jiri Kosina <jikos@...nel.org>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Andrew Duggan <aduggan@...aptics.com>,
	Gabriele Mazzotta <gabriele.mzt@...il.com>,
	Seth Forshee <seth.forshee@...onical.com>,
	Dan Carpenter <dan.carpenter@...cle.com>,
	linux-input@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND] Lenovo Yoga 900 touchpad issues

On Dec 17 2015 or thereabouts, Nish Aravamudan wrote:
> Hi Benjamin,
> 
> On Thu, Dec 17, 2015 at 1:53 AM, Benjamin Tissoires
> <benjamin.tissoires@...hat.com> wrote:
> > On Dec 16 2015 or thereabouts, Nish Aravamudan wrote:
> >> Hi Jiri,
> >>
> >> On Wed, Dec 16, 2015 at 5:18 AM, Jiri Kosina <jikos@...nel.org> wrote:
> >> > On Wed, 16 Dec 2015, Mika Westerberg wrote:
> >> >
> >> >> > [Apologies for the resend, didn't realize I hadn't changed my GMail settings
> >> >> > to not use HTML.]
> >> >> >
> >> >> > I have recently purchased a Lenovo Yoga 900 and most everything is working
> >> >> > with a slightly modified 4.4-rc5 (https://lkml.org/lkml/2015/11/30/441 applied
> >> >> > to enable the touchpad itself), I am seeing two issues:
> >> >> >
> >> >> > 1) On suspend/resume, the touchpad is non-functional. A `modprobe -r i2c-hid;
> >> >> >  modprobe i2c-hid` "fixes" it.
> >> >> >
> >> >> > The kernel emits:
> >> >> >
> >> >> > i2c_hid i2c-SYNA2B29:00: failed to reset device.
> >> >> > dpm_run_callback(): i2c_hid_resume+0x0/0xc0 [i2c_hid] returns -61
> >> >> > PM: Device i2c-SYNA2B29:00 failed to resume: error -61
> >> >> >
> >> >> > During the resume. So perhaps this is a timing issue (given that once
> >> >> > resumed, the
> >> >> > module reload does work?).
> >> >>
> >> >> Linus noticed this as well and Jiri suggested the below patch which
> >> >> seemed to fix the issue (although it increased resume time a bit).
> >> >>
> >> >> I was supposed to get one Lenovo Yoga 900 here to debug this issue but
> >> >> I'm still waiting for it (sloow big corporation bureaucracy takes some
> >> >> time to get things purchased outside).
> >> >>
> >> >> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> >> >> index 55d8f9d..52dd03a0 100644
> >> >> --- a/drivers/hid/i2c-hid/i2c-hid.c
> >> >> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> >> >> @@ -1121,10 +1121,16 @@ static int i2c_hid_resume(struct device *dev)
> >> >>       struct i2c_client *client = to_i2c_client(dev);
> >> >>       struct i2c_hid *ihid = i2c_get_clientdata(client);
> >> >>       struct hid_device *hid = ihid->hid;
> >> >> -     int wake_status;
> >> >> +     int wake_status, tries = 3;
> >> >>
> >> >>       enable_irq(ihid->irq);
> >> >> -     ret = i2c_hid_hwreset(client);
> >> >> +
> >> >> +     do {
> >> >> +             ret = i2c_hid_hwreset(client);
> >> >> +             if (ret)
> >> >> +                     msleep(1000);
> >> >> +     } while (tries-- > 0 && ret);
> >> >> +
> >> >>       if (ret)
> >> >>               return ret;
> >> >
> >> > As a possible alternative, please test the patch above on top of for-next
> >> > branch of
> >> >
> >> >         git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid.git
> >> >
> >> > It contains 64bebefcf3 ("HID: enable hid device to suspend/resume
> >> > asynchronously") and knowing whether that changes something might be
> >> > interesting datapoint as well.
> >>
> >> What should I be looking for to be different wrt. that tree? Should I
> >> not see the failure to reset the device? Or would it be (relatively)
> >> speedier than the stock kernel?
> >>
> >
> > Basically, does the resume time gets better? Linus experienced something
> > like 9 secs of resume before this patch, and now I hope it should be
> > saner (the touchpad might still be a little bit long to respond).
> >
> > Also, we have a bug report concerning this laptop and it looks like the
> > i2c controller needs to be updated (see
> > https://bugzilla.redhat.com/show_bug.cgi?id=1275718).
> >
> > I am not entirely sure why those on the rhbz needs to update the i2c
> > controller while you don't have to, but it may also be worth checking if
> > the i2c patch series mentioned in this rhbz (comment #20) fixes by itself
> > the resume issue (without Jiri's patch).
> 
> Yep, I applied the series from https://lkml.org/lkml/2015/11/30/441
> already. Without that series, I don't have a working touchscreen and
> touchpad. Touchpad resume doesn't work with just that series.

Oh, OK then. Now I start understanding the whole thing.

> 
> With that series + Jiri's patch it seems to resume pretty quickly. But
> I guess I don't see exactly what would change with the resume if the
> same loop is present on top of hid:for-next? Still on my list to test,
> though.

The difference is that now, if the touchpad takes 5 seconds to resume,
it should not block the whole resume time given that it is run in its
own thread.

> 
> Also, even with that series, there does appear maybe there is an I2C
> issue, though:
> 
> i2c_hid i2c-ITE8396:00: error in i2c_hid_init_report size:19 / ret_size:18

I wouldn't worry too much about that. The device does not correctly answer,
but most of the time, this is harmless.

> 
> as I mentioned in my first e-mail; which might be affecting the IIO sensors?

If iio-sensor-proxy works under gnome, there is no need to panic :)

Cheers,
Benjamin
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