[Xen-changelog] [xen master] mwait-idle: update support for Silvermont Core in Baytrail SOC

[patchbot@xxxxxxx]

commit ad8a366760aacb54b2e303b9b082eb95aab5cd42
Author:     Len Brown <len.brown@xxxxxxxxx>
AuthorDate: Wed May 20 13:23:49 2015 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed May 20 13:23:49 2015 +0200

    mwait-idle: update support for Silvermont Core in Baytrail SOC
    
    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>
    [Linux commit d7ef76717322c8e2df7d4360b33faa9466cb1a0d]
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/cpu/mwait-idle.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/cpu/mwait-idle.c b/xen/arch/x86/cpu/mwait-idle.c
index fbe0582..bea31b1 100644
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -196,28 +196,22 @@ static const struct cpuidle_state byt_cstates[] = {
                .target_residency = 1,
        },
        {
-               .name = "C1E-BYT",
-               .flags = MWAIT2flg(0x01),
-               .exit_latency = 15,
-               .target_residency = 30,
-       },
-       {
                .name = "C6N-BYT",
                .flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
-               .exit_latency = 40,
+               .exit_latency = 300,
                .target_residency = 275,
        },
        {
                .name = "C6S-BYT",
                .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
-               .exit_latency = 140,
+               .exit_latency = 500,
                .target_residency = 560,
        },
        {
                .name = "C7-BYT",
                .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 1200,
-               .target_residency = 1500,
+               .target_residency = 4000,
        },
        {
                .name = "C7S-BYT",
--
generated by git-patchbot for /home/xen/git/xen.git#master

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