On Wed, 4 Oct 2023 10:25:47 +0900
Damien Le Moal <dlemoal@xxxxxxxxxx> wrote:
> On 10/4/23 05:07, Petr Tesařík wrote:
> > I just want to confirm that my understanding of the issue is correct
> > now. After applying the patch below, my laptop has just survived half a
> > dozen suspend/resume cycles with autosuspend enabled for the SATA SSD
> > disk. Without the patch, it usually freezes on first attempt.
> >
> > diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> > index a371b497035e..87000f89319e 100644
> > --- a/drivers/ata/libata-scsi.c
> > +++ b/drivers/ata/libata-scsi.c
> > @@ -4768,6 +4768,14 @@ void ata_scsi_dev_rescan(struct work_struct *work)
> > ata_for_each_dev(dev, link, ENABLED) {
> > struct scsi_device *sdev = dev->sdev;
> >
> > + /*
> > + * If the queue accepts only PM, bail out.
> > + */
> > + if (blk_queue_pm_only(sdev->request_queue)) {
> > + ret = -EAGAIN;
> > + goto unlock;
> > + }
> > +
> > /*
> > * If the port was suspended before this was scheduled,
> > * bail out.
>
> This seems sensible to me: scsi_rescan_device() only checks that the device is
> running, without checking that the device queue is also resumed. So the right
> place for this check is scsi_rescan_device():
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 3db4d31a03a1..b05a55f498a2 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -1627,12 +1627,13 @@ int scsi_rescan_device(struct scsi_device *sdev)
> device_lock(dev);
>
> /*
> - * Bail out if the device is not running. Otherwise, the rescan may
> - * block waiting for commands to be executed, with us holding the
> - * device lock. This can result in a potential deadlock in the power
> - * management core code when system resume is on-going.
> + * Bail out if the device or its queue are not running. Otherwise,
> + * the rescan may block waiting for commands to be executed, with us
> + * holding the device lock. This can result in a potential deadlock
> + * in the power management core code when system resume is on-going.
> */
> - if (sdev->sdev_state != SDEV_RUNNING) {
> + if (sdev->sdev_state != SDEV_RUNNING ||
> + blk_queue_pm_only(sdev->request_queue)) {
> ret = -EWOULDBLOCK;
> goto unlock;
> }
>
> Can you try the above to confirm it works for you ? It should, as that is
> essentially the same as you did.
After revertung my patch and applying yours, my system can still resume
from S3. Congrats!
Tested-by: Petr Tesarik <petr@xxxxxxxxxxx>
Petr T
