Re: Disabling intel-wmi-thunderbolt on devices without Thunderbolt / detecting if a device has Thunderbolt
From: Mika Westerberg <mika.westerberg@linux.intel.com>
Date: 2021-10-25 15:14:41
On Mon, Oct 25, 2021 at 04:54:41PM +0200, Hans de Goede wrote:
quoted
Yes that's exactly what is supposed to happen that this attribute is made. What exactly happens when you write into it?The _SB.CGWR ACPI method gets called, with arguments coming from ACPI settings stored in memory. Depending on those settings this function either directly pokes some MMIO or tries to talk to an I2C GPIO expander which is not present on the Surface Go, causing it to MMIO poke an I2C controller which it should not touch. In either case the AML code ends up poking stuff it should not touch and the entire force_power sysfs attribute should simply not be there on devices without thunderbolt.
That's right - it should not be there in the first place if there is no Thunderbolt controller on that thing. I guess most of the systems that have this actually do support Thunderbolt so maybe we can work this around by quirking all the Surface models in that driver?