Re: [Xen-devel] [PATCH] acpi: do not flush cache if cx->type != ACPI_STATE_C3

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 13.04.12 at 04:14, "Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx> wrote:
> This should not be enough. No need to check bm when going to C2.
> How about the following patch:

That looks right, but I'd prefer to simplify it a little:

--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -493,7 +493,9 @@ static void acpi_processor_idle(void)
          * not set. In that case we cannot do much, we enter C3
          * without doing anything.
          */
-        if ( power->flags.bm_check && power->flags.bm_control )
+        if ( cx->type != ACPI_STATE_C3 )
+            /* nothing to be done here */;
+        else if ( power->flags.bm_check && power->flags.bm_control )
         {
             spin_lock(&c3_cpu_status.lock);
             if ( ++c3_cpu_status.count == num_online_cpus() )
@@ -515,7 +517,8 @@ static void acpi_processor_idle(void)
         /* Invoke C3 */
         acpi_idle_do_entry(cx);
 
-        if ( power->flags.bm_check && power->flags.bm_control )
+        if ( (cx->type == ACPI_STATE_C3) &&
+             power->flags.bm_check && power->flags.bm_control )
         {
             /* Enable bus master arbitration */
             spin_lock(&c3_cpu_status.lock);

Also, Yang, you didn't provide a S-o-b - are you okay with me adding
it?

If you're both okay with above patch, I'll see that I get it committed.

Jan


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