svn commit: r244758 - head/sys/arm/broadcom/bcm2835
Oleksandr Tymoshenko
gonzo at freebsd.org
Fri Dec 28 02:49:46 UTC 2012
On 12/27/2012 5:38 PM, Oleksandr Tymoshenko wrote:
> Author: gonzo
> Date: Fri Dec 28 01:38:43 2012
> New Revision: 244758
> URL: http://svnweb.freebsd.org/changeset/base/244758
>
> Log:
> Fix event timer on Raspberry Pi
>
> - Disable interrupt when updating compare value in order to
> make this operation atomical
>
> - Increase minimum period for event timer. Systimer on BCM2835
> is compare timer, so if minimum period is too small it might
> be less then fraction of time between "read current value" and
> "set compare timer" operations. It means that when timer is armed
> actual counter value is more then compare value and it will take
> whole cycle (~32sec for 1MHz timer) to fire interrupt.
>
It's not 32, it's ~4294 seconds
Spotted by: Ian Lepore
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