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    SubjectRE: [PATCH v3 1/1] scsi: pm: Balance pm_only counter of request queue during system resume
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    >
    > On 2020-04-29 21:10, Can Guo wrote:
    > > During system resume, scsi_resume_device() decreases a request queue's
    > > pm_only counter if the scsi device was quiesced before. But after that,
    > > if the scsi device's RPM status is RPM_SUSPENDED, the pm_only counter is
    > > still held (non-zero). Current scsi resume hook only sets the RPM status
    > > of the scsi device and its request queue to RPM_ACTIVE, but leaves the
    > > pm_only counter unchanged. This may make the request queue's pm_only
    > > counter remain non-zero after resume hook returns, hence those who are
    > > waiting on the mq_freeze_wq would never be woken up. Fix this by calling
    > > blk_post_runtime_resume() if pm_only is non-zero to balance the pm_only
    > > counter which is held by the scsi device's RPM ops.
    >
    > How was this issue discovered? How has this patch been tested?

    I think this insight was originally gained as part of commit fb276f770118
    (scsi: ufs: Enable block layer runtime PM for well-known logical units)

    But I will let Can reply on that.

    Thanks,
    Avri

    >
    > Thanks,
    >
    > Bart.
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