Re: [PATCH 4/5] platform/x86: x86-android-tablets: Workaround Lenovo Yoga Tablet 2 830/1050 poweroff hang

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

Hi,

On 2/23/22 15:58, Andy Shevchenko wrote:
> On Wed, Feb 23, 2022 at 02:31:52PM +0100, Hans de Goede wrote:
>> These tablets' DSDT does not set acpi_gbl_reduced_hardware, so
>> acpi_power_off gets used as pm_power_off handler. This causes "poweroff"
>> on these tablets to hang hard. Requiring pressing the powerbutton for
>> 30 seconds *twice* followed by a normal 3 second press to recover.
>>
>> Avoid this by overriding the global pm_power_off handler to do
>> an EFI poweroff instead.
> 
> Oh, you eventually found the root cause (reduced HW bit)?

I'm not sure, it is possible that not setting the reduced HW bit
is actually correct for this hw, but that does lead to using
acpi_power_off which seems broken on this system.

I've updated the commit message while merging this to reflect
that using acpi_power_off is the problem, rather then not setting
the reduced HW bit.

Also note that the issue of reboot being the same as poweroff once
the system has been rebooted at least once is still unresolved.

Regards,

Hans