Re: [linux-pm] Resume from Memory very slow on 2.6.37+

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Tuesday, January 18, 2011, Jeff Chua wrote:
> On Tue, Jan 18, 2011 at 2:55 AM, Brown, Len <len.brown@intel.com> wrote:
> > added Linux-acpi to cc
> >
> > any difference if you boot with acpi_sleep=nonvs ?
> 
> That works.
> 
> On Tue, Jan 18, 2011 at 8:14 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> >> What happens if you replace the acpi_os_map_memory() in
> >> suspend_nvs_save() with ioremap_cache() and the acpi_os_unmap_memory() in
> >> suspend_nvs_free() with iounmap() ?
> >
> > IOW, can you please test if the patch below makes a difference?
> >  drivers/acpi/nvs.c |    6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> That works too.

Interesting.

Do you have CONFIG_RCU_CPU_STALL_DETECTOR set?  If not, please set it.  Then,
set CONFIG_RCU_CPU_STALL_TIMEOUT to something like 10 (in either case), run
a suspend-resume cycle and see if there are any CPU stalls reported in the
logs. 

We can avoid calling synchronize_rcu() in suspend_nvs_free(), but I'd like
to know _why_ it's stalling in there.

> Now I have another problem which might be totally unrelated. Just
> realized that my notebook can't suspend to "disk" ... used to work
> last week. So, something has changed as well. May be someone has
> already reported/fixed this.

Not that I know of.  What do you mean by "can't suspend"?

Rafael