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

[Rainer Finke <rainer@finke.cc>]

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!

Regards,

Rainer Finke