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