linux-kernel - Re: [bisected][bug] commit e978aa7d7d57d04eb5f88 breaks suspend on laptop.

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Date:	Sat, 12 Nov 2011 02:50:13 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	"Tomas M." <tmezzadra@...il.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	deepthi@...ux.vnet.ibm.com, g.trinabh@...il.com, j-pihet@...com,
	khilman@...com, arjan@...ux.intel.com, len.brown@...el.com,
	Arjan van de Ven <arjan@...radead.org>,
	Len Brown <lenb@...nel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ferenc Wagner <wferi@...f.hu>
Subject: Re: [bisected][bug] commit e978aa7d7d57d04eb5f88 breaks suspend on laptop.

On Saturday, November 12, 2011, Rafael J. Wysocki wrote:
> On Friday, November 11, 2011, Tomas M. wrote:
> > yes, that helps.
> 
> What does "cat /sys/devices/system/cpu/cpuidle/current_driver" show?

If that's "acpi_idle", the appended patch should help (it works for
me at least).

Thanks,
Rafael

---
From: Rafael J. Wysocki <rjw@...k.pl>
Subject: ACPI / cpuidle: Remove acpi_idle_suspend (to fix suspend regression)

After commit e978aa7d7d57d04eb5f88a7507c4fb98577def77 (cpuidle: Move
dev->last_residency update to driver enter routine; remove
dev->last_state) setting acpi_idle_suspend to 1 by
acpi_processor_suspend() causes the ACPI cpuidle routines to return
error codes continuously, which in turn causes cpuidle to lock up
(hard).  However, acpi_idle_suspend doesn't appear to be useful for
any purpose (it's racy and doesn't really provide any real
protection), so it can be removed, which makes the problem go away.

Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
 drivers/acpi/processor_idle.c |   29 -----------------------------
 1 file changed, 29 deletions(-)

Index: linux/drivers/acpi/processor_idle.c
===================================================================
--- linux.orig/drivers/acpi/processor_idle.c
+++ linux/drivers/acpi/processor_idle.c
@@ -224,7 +224,6 @@ static void lapic_timer_state_broadcast(
 /*
  * Suspend / resume control
  */
-static int acpi_idle_suspend;
 static u32 saved_bm_rld;
 
 static void acpi_idle_bm_rld_save(void)
@@ -243,21 +242,13 @@ static void acpi_idle_bm_rld_restore(voi
 
 int acpi_processor_suspend(struct acpi_device * device, pm_message_t state)
 {
-	if (acpi_idle_suspend == 1)
-		return 0;
-
 	acpi_idle_bm_rld_save();
-	acpi_idle_suspend = 1;
 	return 0;
 }
 
 int acpi_processor_resume(struct acpi_device * device)
 {
-	if (acpi_idle_suspend == 0)
-		return 0;
-
 	acpi_idle_bm_rld_restore();
-	acpi_idle_suspend = 0;
 	return 0;
 }
 
@@ -763,13 +754,6 @@ static int acpi_idle_enter_c1(struct cpu
 
 	local_irq_disable();
 
-	/* Do not access any ACPI IO ports in suspend path */
-	if (acpi_idle_suspend) {
-		local_irq_enable();
-		cpu_relax();
-		return -EINVAL;
-	}
-
 	lapic_timer_state_broadcast(pr, cx, 1);
 	kt1 = ktime_get_real();
 	acpi_idle_do_entry(cx);
@@ -810,13 +794,6 @@ static int acpi_idle_enter_simple(struct
 
 	local_irq_disable();
 
-	if (acpi_idle_suspend) {
-		local_irq_enable();
-		cpu_relax();
-		return -EINVAL;
-	}
-
-
 	if (cx->entry_method != ACPI_CSTATE_FFH) {
 		current_thread_info()->status &= ~TS_POLLING;
 		/*
@@ -895,12 +872,6 @@ static int acpi_idle_enter_bm(struct cpu
 	if (unlikely(!pr))
 		return -EINVAL;
 
-
-	if (acpi_idle_suspend) {
-		cpu_relax();
-		return -EINVAL;
-	}
-
 	if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
 		if (drv->safe_state_index >= 0) {
 			return drv->states[drv->safe_state_index].enter(dev,
--
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