[Xen-devel] [PATCH] xen: Re-upload processor PM data to hypervisor after S3 resume

[Ben Guthro <benjamin.guthro@xxxxxxxxxx>]

Upon resume, it was found that ACPI C-states were missing from non-boot CPUs.
This change registers a syscore_ops handler for this case, and performs a
subset of the xen_acpi_processor_init() functionality to achieve this case.

Signed-Off-By: Ben Guthro <benjamin.guthro@xxxxxxxxxx>
---
 drivers/xen/xen-acpi-processor.c |   24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
index 316df65..1510c64 100644
--- a/drivers/xen/xen-acpi-processor.c
+++ b/drivers/xen/xen-acpi-processor.c
@@ -25,6 +25,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/types.h>
+#include <linux/syscore_ops.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 #include <acpi/processor.h>
@@ -467,6 +468,26 @@ static void free_acpi_perf_data(void)
        free_percpu(acpi_perf_data);
 }
 
+static void xen_acpi_processor_resume(void)
+{
+       int i;
+       printk(KERN_INFO "Resuming Xen processor info\n");
+
+       for_each_possible_cpu(i) {
+               struct acpi_processor *_pr;
+               _pr = per_cpu(processors, i /* APIC ID */);
+               if (!_pr)
+                       continue;
+
+               __clear_bit(_pr->acpi_id, acpi_ids_done);
+               (void)upload_pm_data(_pr);
+       }
+}
+
+static struct syscore_ops xap_syscore_ops = {
+       .resume                 = xen_acpi_processor_resume,
+};
+
 static int __init xen_acpi_processor_init(void)
 {
        struct acpi_processor *pr_backup = NULL;
@@ -532,6 +553,8 @@ static int __init xen_acpi_processor_init(void)
        if (rc)
                goto err_unregister;
 
+       register_syscore_ops(&xap_syscore_ops);
+
        return 0;
 err_unregister:
        for_each_possible_cpu(i) {
@@ -550,6 +573,7 @@ static void __exit xen_acpi_processor_exit(void)
        int i;
 
        kfree(acpi_ids_done);
+       unregister_syscore_ops(&xap_syscore_ops);
        for_each_possible_cpu(i) {
                struct acpi_processor_performance *perf;
                perf = per_cpu_ptr(acpi_perf_data, i);
-- 
1.7.9.5


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