On Wed, Feb 05, 2020 at 08:30:48AM -0800, Guenter Roeck wrote: > On Wed, Feb 05, 2020 at 05:24:35PM +0200, Mika Westerberg wrote: > > On Wed, Feb 05, 2020 at 04:05:29PM +0100, Jean Delvare wrote: > > > Hi all, > > > > Hi, > > > > > Is there a way to prevent the ACPI WDAT watchdog interface from being > > > used and force the use of a native watchdog driver instead? > > > > > > I have a customer who reports a regression on kernel upgrade. Old > > > kernel (v4.4) uses iTCO_wdt and watchdog works, new kernel (v4.12) uses > > > wdat_wdt and watchdog doesn't work (instant reboot when opening the > > > device). While I'm going to look for fixes to backport, I think it > > > would be pretty convenient to have a way to just revert to the working > > > driver until the new driver is fixed somehow. But I can't see any way > > > to do that at the moment, short of disabling ACPI completely, which is > > > definitely too extreme to be considered. > > > > > > Am I missing something? > > > > You should be able to revert to iTCO_wdt by simply disabling > > CONFIG_WDAT_WDT from .config. Then acpi_has_watchdog() returns false > > which means that iTCO_wdt is used instead. > > That may not be possible in a generic distribution. Right, they would need to build their own kernel. Currently there is no way to do that without changing .config.
