On Tuesday, October 16, 2018 1:01:35 AM CEST Bart Van Assche wrote:
> On Tue, 2018-10-16 at 00:44 +0200, Rafael J. Wysocki wrote:
> > On Tue, Oct 16, 2018 at 12:19 AM Bart Van Assche <bvanassche@xxxxxxx> wrote:
> > >
> > > This patch avoids that the following warning is reported during hibernation:
> >
> > Well, what exactly is the problem and why is the patch the right way
> > to address it?
>
> It is not safe to call ktime_get() after having called timekeeping_suspend().
Right, so this really is an ordering issue in "syscore" suspend.
There are a couple of ways to address this without changing the ACPICA code.
For example, ktime_get_mono_fast_ns() can be used instead of ktime_get()
if the system is in deep suspend, like in the patch below (untested).
---
drivers/acpi/osl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-pm/drivers/acpi/osl.c
===================================================================
--- linux-pm.orig/drivers/acpi/osl.c
+++ linux-pm/drivers/acpi/osl.c
@@ -623,7 +623,8 @@ void acpi_os_stall(u32 us)
*/
u64 acpi_os_get_timer(void)
{
- u64 time_ns = ktime_to_ns(ktime_get());
+ u64 time_ns = ktime_to_ns(unlikely(system_state == SYSTEM_SUSPEND) ?
+ ktime_get_mono_fast_ns() : ktime_get());
do_div(time_ns, 100);
return time_ns;
}
