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

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

On Monday, January 17, 2011, Rafael J. Wysocki wrote:
> On Monday, January 17, 2011, Jeff Chua wrote:
> > I've just tried the recent linux git pull
> > (e78bf5e6cbe837daa6ab628a5f679548742994d3) and suspend-to-memory
> > works, but resume takes a very long time (30 seconds doing nothing).
> > 
> > Bisected and it says first bad commit is
> > ca9b600be38c73b7d25acfb8b7e4e9a9e941d881
> 
> Hmm.  That's probably because acpi_os_unmap_memory() does the
> synchronize_rcu(), but I have no idea why it might cause a problem to
> occur in suspend_nvs_free().
> 
> 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?

Rafael

---
 drivers/acpi/nvs.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Index: linux-2.6/drivers/acpi/nvs.c
===================================================================
--- linux-2.6.orig/drivers/acpi/nvs.c
+++ linux-2.6/drivers/acpi/nvs.c
@@ -80,7 +80,7 @@ void suspend_nvs_free(void)
 			free_page((unsigned long)entry->data);
 			entry->data = NULL;
 			if (entry->kaddr) {
-				acpi_os_unmap_memory(entry->kaddr, entry->size);
+				iounmap(entry->kaddr);
 				entry->kaddr = NULL;
 			}
 		}
@@ -114,8 +114,8 @@ int suspend_nvs_save(void)
 
 	list_for_each_entry(entry, &nvs_list, node)
 		if (entry->data) {
-			entry->kaddr = acpi_os_map_memory(entry->phys_start,
-							  entry->size);
+			entry->kaddr = ioremap_cache(entry->phys_start,
+						     entry->size);
 			if (!entry->kaddr) {
 				suspend_nvs_free();
 				return -ENOMEM;