Re: [Bug 209627] Touchscreen doesn't work anymore since commit 21653a4181ff292480599dad996a2b759ccf050f (regression)

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 10/15/20 12:35 AM, Rainer Finke wrote:
> Hi,
> 
> On 14.10.20 17:13, Hans de Goede wrote:
>> Hi,
>>
>> On 10/13/20 5:45 PM, Hans de Goede wrote:
>>> 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.
>>
>> In the mean time another issue triggered by the same
>> commit has shown up on Microsoft Surface Go models.
>>
>> With te help fo the reporters of that issue I have found
>> on issue with that commit.
>>
>> Can you please try a kernel with the troublesome commit
>> *included* with the attached patch added on top and see
>> if that fixes things?
>>
>> Regards,
>>
>> Hans
> 
> 
> I've compiled linux-git with the provided patch and it worked :-)
> 
> 
> Thank you very much for the great support!

Great thank you for reporting the bug and for fixing the issue.

Regards,

Hans