https://bugzilla.kernel.org/show_bug.cgi?id=204807 --- Comment #58 from Hans de Goede (jwrdegoede@xxxxxxxxxxxxxxxxx) --- (In reply to Mateusz Jończyk from comment #57) > (In reply to Hans de Goede from comment #56) > > Hmm, > > > > asus-wmi-sensors also is not such a great solution, it seems the WMI > > interface is buggy on some boards and causes fans to stop or get stuck at > > max speed, which is quite bad, see: > > > > https://github.com/electrified/asus-wmi-sensors#known-issues > > IMHO, this could be caused by access races, not necessarily by a buggy BIOS. > The driver may simply not implement correct synchronization methods. It may > be necessary to call some ACPI / WMI methods before and after accessing the > sensors to avoid resource conflicts. Perhaps, but usually WMI methods take the locks which they need on entry and release them on exit. I'm not even sure if an ACPI method (which this ultimately is) can hold locks after it exits, I would not be surprised if all acquired locks are automatically dropped on exit from the interpreter. Also note that the README also states that on some motherboards the problems are fixed in later BIOS versions, which also points to a race inside the AML code and not a bug in the driver. > As is written in the documentation: > > The more frequently the WMI interface is polled the greater the potential > for > > this to happen. > > I am also not sure if the driver implements correct locking behavior > kernel-wise. I did not check, but this should not matter, that may mess up the driver's state, but the WMI code is expected to do its own locking at the AML level, to e.g. protect against similar accesses to the super IO through the ACPI thermal region interface. Note I'm not claiming that this is definitely not an issue with the driver, it could be. But I've seen a lot of very buggy AML code and I've yet to find a single vendor which does not write very low quality AML code. It seems there is absolutely no code-review done on the AML code and very little QA. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
