On Sat, Nov 24, 2018 at 10:01:48PM -0800, Krzysztof Olędzki wrote: > I think older kernels should be fine, like I said - everything worked under > 4.4-stable. I suspect this is because of some ACPI / WDAT improvements in > 4.9, or between 4.5 - 4.8 for which we no longer support -stable. Mika, do > you know which change exactly introduce this side effect? IIRC it was the introduction of WDAT driver itself in commit 058dfc767008 ("ACPI / watchdog: Add support for WDAT hardware watchdog"). The driver went into v4.9 so I don't think older stable kernels need this.