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    SubjectRe: [RFC PATCH 0/4] mmc: sdhci: Support maximum DMA latency request via PM QoS
    > Ad hoc testing with Lenovo Thinkpad 10 showed a stress
    > test could run for at least 24 hours with the patches,
    > compared to less than an hour without.

    There is a patch in linux-next to delete C1E from BYT,
    since it is problematic on multiple platforms.
    I don't suppose that just disabling that state without disabling C6
    is sufficient to fix the Thinkpad 10? (I'm betting not, but
    it can't hurt to try -- you can use the "disable" attribute for the state
    in /sys/devices/system/cpu/cpu*/cpuidle/stateN)

    I think your choice of the PM_QOS sub-system here is the right one,
    and that your selection of 20usec threshold is also a good choice
    for what you want to do -- though on non-intel_idle machine somplace,
    there may be some ACPI BIOS _CST with random number for C6 latency.

    It would be interesting to see how your C6 residency (turbostat
    --debug will show this to you)
    and your battery life are changed by disabling C6 during MMC activity.

    Len Brown, Intel Open Source Technology Center

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