On Thu, Oct 03, 2024 at 07:47:41AM +0900, Damien Le Moal wrote: > On 10/3/24 06:20, Niklas Cassel wrote: > > On Tue, Sep 24, 2024 at 12:42:10PM +0200, W wrote: > >>> > >>> Given that you had 6.4.12 working OK, it is likely some commit that introduced a > >>> regression. If you can git bisect it, we will have a better idea how to remove > >>> the regression. > >> > >> Please take a look at bugzilla report: > >> https://bugzilla.kernel.org/show_bug.cgi?id=219296 - there are the details. > >> > >> I'm wondering what is the better way for communication - here on mailing > >> list or put the comments in bugzilla ticket? > >> Probably here will be better idea... > >> > >> W > >> > > > > Hello W, > > > > Could you please try the following patch, > > and see if it helps: > > > > > > From dba01b7d68fffc26f3abf3252296082311a767a0 Mon Sep 17 00:00:00 2001 > > From: Niklas Cassel <cassel@xxxxxxxxxx> > > Date: Wed, 2 Oct 2024 21:40:41 +0200 > > Subject: [PATCH] ata: libata: do not spin down disk on PM event freeze > > > > Currently, ata_eh_handle_port_suspend() will return early if > > ATA_PFLAG_PM_PENDING is not set, or if the PM event has flag > > PM_EVENT_RESUME set. > > > > This means that the following PM callbacks: > > .suspend = ata_port_pm_suspend, > > .freeze = ata_port_pm_freeze, > > .poweroff = ata_port_pm_poweroff, > > .runtime_suspend = ata_port_runtime_suspend, > > will actually make ata_eh_handle_port_suspend() perform some work. > > > > ata_eh_handle_port_suspend() will spin down the disks (by calling > > ata_dev_power_set_standby()), regardless of the PM event. > > > > Documentation/driver-api/pm/devices.rst, section "Entering Hibernation", > > explicitly mentions that .freeze() does not have to be put the device in > > a low-power state, and actually recommends not doing so. Thus, let's not > > spin down the disk for the .freeze() callback. (The disk will instead be > > spun down during the succeeding .poweroff() callback.) > > > > Fixes: aa3998dbeb3a ("ata: libata-scsi: Disable scsi device manage_system_start_stop") > > Signed-off-by: Niklas Cassel <cassel@xxxxxxxxxx> > > --- > > drivers/ata/libata-eh.c | 18 ++++++++++++++---- > > 1 file changed, 14 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c > > index 3f0144e7dc80..45a0d9af2d54 100644 > > --- a/drivers/ata/libata-eh.c > > +++ b/drivers/ata/libata-eh.c > > @@ -4099,10 +4099,20 @@ static void ata_eh_handle_port_suspend(struct ata_port *ap) > > > > WARN_ON(ap->pflags & ATA_PFLAG_SUSPENDED); > > > > - /* Set all devices attached to the port in standby mode */ > > - ata_for_each_link(link, ap, HOST_FIRST) { > > - ata_for_each_dev(dev, link, ENABLED) > > - ata_dev_power_set_standby(dev); > > + /* > > + * We will reach this point for all of the PM events: > > + * PM_EVENT_SUSPEND (if runtime pm, PM_EVENT_AUTO will also be set) > > + * PM_EVENT_FREEZE, and PM_EVENT_HIBERNATE. > > + * > > + * We do not want to perform disk spin down for PM_EVENT_FREEZE. > > + * (Spin down will be performed by the succeeding PM_EVENT_HIBERNATE.) > > + */ > > + if (!(ap->pm_mesg.event & PM_EVENT_FREEZE)) { > > This feels odd: not doing anything to the drive for PM_EVENT_FREEZE will still > endup freezing the port, which will later cause a reset. And we still endup > calling the port suspend op and ata_acpi_set_state(), which seems to be doing > nothing for freeze... Hello Damien, Hibernation is done by three consecutive PM events, in the following order: 1) PM_EVENT_FREEZE 2) PM_EVENT_THAW 3) PM_EVENT_HIBERNATE Hibernate before commit aa3998dbeb3a ("ata: libata-scsi: Disable scsi device manage_system_start_stop"): -On event PM_EVENT_FREEZE: ata_eh_handle_port_suspend() would call ata_eh_freeze_port() and then call ap->ops->port_suspend(). -On event PM_EVENT_THAW: ata_port_resume() would trigger EH with ATA_EH_RESET, which triggers a all to ata_eh_reset(), which will thaw the port, and then later ata_eh_handle_port_resume() would call ap->ops->port_resume(). -On event PM_EVENT_HIBERNATE: same as PM_EVENT_FREEZE. After commit aa3998dbeb3a ("ata: libata-scsi: Disable scsi device manage_system_start_stop"), on event PM_EVENT_FREEZE, and on event PM_EVENT_HIBERNATE, ata_eh_handle_port_suspend() would call ata_eh_freeze_port() and then call ap->ops->port_suspend(), but it would also call ata_dev_power_set_standby() to spin down the disk. So what my propsed patch does is simply to restore ata_eh_handle_port_suspend() to the behavior before commit aa3998dbeb3a for event PM_EVENT_FREEZE, but for event PM_EVENT_HIBERNATE, ata_eh_handle_port_suspend() will continue to spin down the disk. > > So I wonder if a simpler approach would not be to simply remove the > ata_port_pm_freeze() method entirely and do nothing for freeze events ? I do not think that is a good option, as: https://docs.kernel.org/driver-api/pm/devices.html#entering-hibernation clearly states that: "The ->freeze methods should quiesce the device so that it doesn’t generate IRQs or DMA." That is what we do when calling ata_eh_freeze_port(). I think my propsed patch is the simplest thing that we can do to restore the behavior of ata_eh_handle_port_suspend() for event PM_EVENT_FREEZE, as it was before commit aa3998dbeb3a. Thus, I will send out this proposed patch as a real patch shortly. Kind regards, Niklas
