Re: [PATCH 2/3] platform/x86: thinkpad_acpi: convert conditional mutex locks to ACQUIRE_ERR()

[Ali Ahmet Memiş]

Tested on a ThinkPad T490 with lockdep enabled, details in my reply to 1/3.

One question on brightness_get(). It is the backlight_ops->get_brightness
callback and has returned 0 on failure so far, with the conversion it now
returns a negative errno instead. In backlight.c that changes what callers
see. actual_brightness_show() passes the negative value out to the sysfs
read rather than reporting 0, and backlight_force_update() logs "Could not
update brightness from device" when the EC read fails. Is that intended?

I couldn't test this, since the T490 backlight is owned by i915, so
thinkpad-acpi registers no backlight device on this machine.

Tested-by: Ali Ahmet Memiş <aliamemis@xxxxxxxxxxx>