On Wed, Mar 29, 2017 at 04:24:08PM +0100, Mark Rutland wrote:
On Tue, Mar 28, 2017 at 05:02:20PM +0200, Daniel Lezcano wrote:
On Wed, Mar 22, 2017 at 12:31:14AM +0800, fu.wei@linaro.org wrote:
From: Fu Wei fu.wei@linaro.org
When system init with device-tree, we don't know which node will be initialized first. And the code in arch_timer_common_init should wait until per-cpu timer and MMIO timer are both initialized. So we need arch_timer_needs_probing to detect the init status of system.
But currently the code is dispersed in arch_timer_needs_probing and arch_timer_common_init. And the function name doesn't specify that it's only for device-tree. This is somewhat confusing.
Can the following patch help you to solve nicely the situation ?
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1360007.html
This does not help.
The needs_probing logic is all there to bodge around a problem with registering sched_clock, when you have two sources of the same frequency, but one is otherwise better.
The sysreg clocksource has much lower latency than the MMIO clocksource, so we always want to use that as the sched_clock if we have it. Currently, the code ensures this by deferring registration of sched_clock.
Ideally, we'd figure that out dynamically, or we'd have a rating argument.
Ok, I see. Thanks.