tree c56cda00d7d2701935a67bcdbbe6c5ec0c969edc
parent 0f9fee4cdebfbe695c297e5b603a275e2557c1cc
author Helge Deller <deller@gmx.de> 1638649306 +0100
committer Helge Deller <deller@gmx.de> 1638650164 +0100

parisc: Mark cr16 CPU clocksource unstable on all SMP machines

In commit c8c3735997a3 ("parisc: Enhance detection of synchronous cr16
clocksources") I assumed that CPUs on the same physical core are syncronous.
While booting up the kernel on two different C8000 machines, one with a
dual-core PA8800 and one with a dual-core PA8900 CPU, this turned out to be
wrong. The symptom was that I saw a jump in the internal clocks printed to the
syslog and strange overall behaviour.  On machines which have 4 cores (2
dual-cores) the problem isn't visible, because the current logic already marked
the cr16 clocksource unstable in this case.

This patch now marks the cr16 interval timers unstable if we have more than one
CPU in the system, and it fixes this issue.

Fixes: c8c3735997a3 ("parisc: Enhance detection of synchronous cr16 clocksources")
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.15+