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From: Hans de Goede <hdegoede@redhat.com>
To: Rainer Finke <rainer@finke.cc>, linux-i2c@vger.kernel.org
Cc: mika.westerberg@linux.intel.com, wsa@kernel.org, sashal@kernel.org
Subject: Re: [Bug 209627] Touchscreen doesn't work anymore since commit 21653a4181ff292480599dad996a2b759ccf050f (regression)
Date: Tue, 13 Oct 2020 17:45:49 +0200	[thread overview]
Message-ID: <cb544a8b-98e8-2f43-4984-bc0422a05703@redhat.com> (raw)
In-Reply-To: <ab71ef62-64c8-ff31-c5aa-43ad454d1143@finke.cc>

Hi,

On 10/12/20 9:52 PM, Rainer Finke wrote:
> After upgrading from Linux 5.4.68 to Linux 5.4.69, the touchscreen of my Huawei Matebook 12 doesn't work anymore. The same issue happens with Linux >= 5.8.13.
> 
> I've compiled Linux from git to verify if it was fixed, but it doesn't help. But when reverting the commit 21653a4181ff292480599dad996a2b759ccf050f the touchscreen works fine again.
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.8.13&id=953fc770d069b167266d9d9ccfef0455fcfdc070
> 
> For reference my bug reports:
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=209627
> 
> https://bugs.archlinux.org/task/68178#comment193400
> 
> 
> Hardware:
> 
> - CPU Intel Core m3-6Y30
> 
> - GPU Intel Graphics 515

Thank you for your bug report and I'm sorry to hear about this problem.

The commit in question fixes the touchpad not working on several
recent Lenovo models. What it does it makes the method (opregion) to
access the i2c bus from ACPI code available to the ACPI code before
calling the status method of ACPI devices on that i2c-bus.
This status method tells us if the device is actually present or not
and on those Thinkpads the status method did an i2c check, so we
needed to register the i2c opregion before checking for new devices.

Registering the i2c opregion earlier seemed like an obvious
solution, but I was already afraid we would hit an issue on some
device because of this, because of ACPI being ACPI.

It seems that the ACPI status method for your device probably
also does something with the i2c bus when the i2c opregion
is available, but for some reason that is not working...

The next step in debugging this would be to take a look at
the ACPI tables for your device, can you please run:

sudo acpidump -o acpidump.Huawei-Matebook-12

And then send out an email with the generated
acpidump.Huawei-Matebook-12 file attached?

Note please drop the list from the Cc when sending the
email with the attachment.

What would also be useful (for a possible workaround) would
be the output of:

grep . /sys/class/dmi/id/* 2> /dev/null

Please run this as a normal user (*) and copy and paste
the output into your next email.

Regards,

Hans



*) this will exclude serialnumbers for your device which
are only readable by root



  reply	other threads:[~2020-10-13 15:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-12 19:52 [Bug 209627] Touchscreen doesn't work anymore since commit 21653a4181ff292480599dad996a2b759ccf050f (regression) Rainer Finke
2020-10-13 15:45 ` Hans de Goede [this message]
2020-10-14 15:13   ` Hans de Goede
2020-10-14 22:35     ` Rainer Finke
2020-10-15  7:56       ` Hans de Goede

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