[linux-yocto] [PATCH 5/6] intel_idle: Update support for Silvermont Core in Baytrail SOC

[wei.tee.ng at intel.com]

From: Len Brown <len.brown at intel.com>

On some Silvermont-Core/Baytrail-SOC systems,
C1E latency is higher than original specifications.
Although C1E is still enumerated in CPUID.MWAIT.EDX,
we delete the state from intel_idle to avoid latency impact.

Under some conditions, the latency of the C6N-BYT and C6S-BYT states
may exceed the specified values of 40 and 140 usec, respectively.
Increase those values to 300 and 500 usec; to assure
that the hardware does not violate constraints that may be set
by the Linux PM_QOS sub-system.

Also increase the C7-BYT target residency to 4.0 ms from 1.5 ms.

Signed-off-by: Len Brown <len.brown at intel.com>
Cc: Kumar P Mahesh <mahesh.kumar.p at intel.com>
Cc: Alan Cox <alan at linux.intel.com>
Cc: Mika Westerberg <mika.westerberg at linux.intel.com>
Cc: <stable at vger.kernel.org>
(cherry picked from commit d7ef76717322c8e2df7d4360b33faa9466cb1a0d)

Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang at intel.com>
---
 drivers/idle/intel_idle.c |   14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index b0e5852..44d1d79 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -218,18 +218,10 @@ static struct cpuidle_state byt_cstates[] = {
 		.enter = &intel_idle,
 		.enter_freeze = intel_idle_freeze, },
 	{
-		.name = "C1E-BYT",
-		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
-		.exit_latency = 15,
-		.target_residency = 30,
-		.enter = &intel_idle,
-		.enter_freeze = intel_idle_freeze, },
-	{
 		.name = "C6N-BYT",
 		.desc = "MWAIT 0x58",
 		.flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
-		.exit_latency = 40,
+		.exit_latency = 300,
 		.target_residency = 275,
 		.enter = &intel_idle,
 		.enter_freeze = intel_idle_freeze, },
@@ -237,7 +229,7 @@ static struct cpuidle_state byt_cstates[] = {
 		.name = "C6S-BYT",
 		.desc = "MWAIT 0x52",
 		.flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
-		.exit_latency = 140,
+		.exit_latency = 500,
 		.target_residency = 560,
 		.enter = &intel_idle,
 		.enter_freeze = intel_idle_freeze, },
@@ -246,7 +238,7 @@ static struct cpuidle_state byt_cstates[] = {
 		.desc = "MWAIT 0x60",
 		.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
 		.exit_latency = 1200,
-		.target_residency = 1500,
+		.target_residency = 4000,
 		.enter = &intel_idle,
 		.enter_freeze = intel_idle_freeze, },
 	{
-- 
1.7.9.5