4.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: Len Brown <len.brown@xxxxxxxxx>
commit d7ef76717322c8e2df7d4360b33faa9466cb1a0d upstream.
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@xxxxxxxxx>
Cc: Kumar P Mahesh <mahesh.kumar.p@xxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxx>
Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/idle/intel_idle.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)
--- 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, },
{
--
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