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Commit c9c860e5 authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by Len Brown
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cpuidle: fix C3 for no bus-master control case 



Port 18eab855
(Enable C3 even when PM2_control is zero) to cpuidle.

Without this patch, some systems will notice a regression
when enabling CPU_IDLE -- C3 would no longer be available.

Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 83788c0c

drivers/acpi/processor_idle.c

+25 −10
Original line number Diff line number Diff line
@@ -1514,24 +1514,39 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev, 
	} else {

		acpi_idle_update_bm_rld(pr, cx);



		/*

		 * disable bus master

		 * bm_check implies we need ARB_DIS

		 * !bm_check implies we need cache flush

		 * bm_control implies whether we can do ARB_DIS

		 *

		 * That leaves a case where bm_check is set and bm_control is

		 * not set. In that case we cannot do much, we enter C3

		 * without doing anything.

		 */

		if (pr->flags.bm_check && pr->flags.bm_control) {

			spin_lock(&c3_lock);

			c3_cpu_count++;

			/* Disable bus master arbitration when all CPUs are in C3 */

			if (c3_cpu_count == num_online_cpus())

				acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);

			spin_unlock(&c3_lock);

		} else if (!pr->flags.bm_check) {

			ACPI_FLUSH_CPU_CACHE();

		}



		t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);

		acpi_idle_do_entry(cx);

		t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);



		spin_lock(&c3_lock);

		/* Re-enable bus master arbitration */

		if (c3_cpu_count == num_online_cpus())

		if (pr->flags.bm_check && pr->flags.bm_control) {

			spin_lock(&c3_lock);

			acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);

			c3_cpu_count--;

			spin_unlock(&c3_lock);

		}

	}



#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)

	/* TSC could halt in idle, so notify users */