[AMD Official Use Only]
> -----Original Message-----
> From: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
> Sent: Sunday, April 3, 2022 20:11
> To: Limonciello, Mario <Mario.Limonciello@xxxxxxx>
> Cc: open list:LIBATA SUBSYSTEM (Serial and Parallel ATA drivers) <linux-
> ide@xxxxxxxxxxxxxxx>; open list <linux-kernel@xxxxxxxxxxxxxxx>;
> hdegoede@xxxxxxxxxx
> Subject: Re: [PATCH v2 2/2] ata: ahci: Protect users from setting policies their
> drives don't support
>
> On 3/3/22 12:49, Mario Limonciello wrote:
> > As the default low power policy applies to more chipsets and drives, it's
> > important to make sure that drives actually support the policy that a user
> > selected in their kernel configuration.
> >
> > If the drive doesn't support slumber, don't let the default policies
> > dependent upon slumber (`min_power` or `min_power_with_partial`) affect
> the
> > disk.
> >
> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
>
> Mario,
>
> Can you resend a rebased version of this, on top of libata for-5.19 branch ?
OK.
>
> > ---
> > Changes from v1->v2:
> > * Move deeper into codepaths
> > * Reset to MED_POWER rather than ignore
> > drivers/ata/libata-sata.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
> > diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
> > index 071158c0c44c..0dc03888c62b 100644
> > --- a/drivers/ata/libata-sata.c
> > +++ b/drivers/ata/libata-sata.c
> > @@ -13,6 +13,7 @@
> > #include <scsi/scsi_device.h>
> > #include <linux/libata.h>
> >
> > +#include "ahci.h"
> > #include "libata.h"
> > #include "libata-transport.h"
> >
> > @@ -368,10 +369,20 @@ int sata_link_scr_lpm(struct ata_link *link, enum
> ata_lpm_policy policy,
> > bool spm_wakeup)
> > {
> > struct ata_eh_context *ehc = &link->eh_context;
> > + struct ata_port *ap = link->ap;
> > + struct ahci_host_priv *hpriv;
> > bool woken_up = false;
> > u32 scontrol;
> > int rc;
> >
> > + hpriv = ap->host->private_data;
> > + if (policy >= ATA_LPM_MIN_POWER_WITH_PARTIAL &&
> > + !(hpriv->cap & HOST_CAP_SSC)) {
> > + dev_warn(ap->host->dev,
> > + "This drive doesn't support slumber; restting policy to
> MED_POWER\n");
>
> Typo here: s/restting/resetting. Also, s/doesn't/does not.
>
> > + policy = ATA_LPM_MED_POWER;
>
> Here, shouldn't we use the default policy defined by
> CONFIG_SATA_LPM_POLICY ?
If they set it too aggressively we still don't want to honor it if the drive
can't do slumber I would expect.
>
> > + }
> > +
> > rc = sata_scr_read(link, SCR_CONTROL, &scontrol);
> > if (rc)
> > return rc;
>
>
> --
> Damien Le Moal
> Western Digital Research
