[PATCH] Add sched_clock to AT91 TCB clocksource driver
Russell King - ARM Linux
linux at arm.linux.org.uk
Mon Aug 1 05:28:06 EDT 2011
On Mon, Aug 01, 2011 at 10:42:35AM +0200, Remy Bohmer wrote:
> OK, I know that too, but the jiffies based fallback does it even
> worse, since it does not run at all... (It only updates in steps of a
> couple of 100msecs and stops after a while, and even does not display
> a real time...) This sched_clock implementation at least works before
> the drivers are being initialised...
You're forgetting that jiffies doesn't jump about. A late initializing
sched_clock could jump.
> Anyway, do you have a better suggestion how to fix this? The tcb
> clocksource is loaded during a arch_initcall(), perhaps we need
> something before that point.
> I do not see an easy way to integrate it in MACHINE_START(.timer).
> Would 'late_time_init' be a better solution?
late_time_init() is not that much better as that still happens after
sched_init() has been called. sched_init() initializes various
structures which involves reading sched_clock().
Why can't it initialize itself at the standard point during the boot
sequence, which is time_init() - which in turn is as you say the
More information about the linux-arm-kernel