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    SubjectRe: [PATCH v2 1/2] Revert "drivers: qcom: rpmh-rsc: Use rcuidle tracepoints for rpmh"
    On Tue, Aug 25, 2020 at 4:22 AM Maulik Shah <mkshah@codeaurora.org> wrote:
    >
    > Commit efde2659b0fe ("drivers: qcom: rpmh-rsc: Use rcuidle tracepoints
    > for rpmh") was written to fix a bug seen in an unmerged series that
    > implemented a struct generic_pm_domain::power_off() callback calling
    > rpmh_flush(). See stack trace below.
    >
    > Call trace:
    > dump_backtrace+0x0/0x174
    > show_stack+0x20/0x2c
    > dump_stack+0xc8/0x124
    > lockdep_rcu_suspicious+0xe4/0x104
    > __tcs_buffer_write+0x230/0x2d0
    > rpmh_rsc_write_ctrl_data+0x210/0x270
    > rpmh_flush+0x84/0x24c
    > rpmh_domain_power_off+0x78/0x98
    > _genpd_power_off+0x40/0xc0
    > genpd_power_off+0x168/0x208
    >
    > Later the final merged solution is to use CPU PM notification to invoke
    > rpmh_flush() and power_off() callback of genpd is not implemented in the
    > driver.
    >
    > CPU PM notifiers are run with RCU enabled/watching (see cpu_pm_notify()
    > and how it calls rcu_irq_enter_irqson() before calling the notifiers).
    >
    > Remove this change since RCU will not be idle during CPU PM notifications
    > hence not required to use _rcuidle tracepoint. Using _rcuidle tracepoint
    > prevented rpmh driver to be loadable module as these are not exported
    > symbols.
    >
    > This reverts commit efde2659b0fe835732047357b2902cca14f054d9.
    >
    > Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
    > Cc: John Stultz <john.stultz@linaro.org>
    > Cc: Stephen Rothwell <sfr@canb.auug.org.au>
    > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
    > Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
    > Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
    > Signed-off-by: Maulik Shah <mkshah@codeaurora.org>

    Hey Maulik!
    Thanks so much for sending out this series! I noticed this hasn't
    made it to -next yet, so would it be good to resubmit it?

    thanks
    -john

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