4.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: Len Brown <[email protected]> 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 <[email protected]> Cc: Kumar P Mahesh <[email protected]> Cc: Alan Cox <[email protected]> Cc: Mika Westerberg <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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, }, { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
