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    SubjectRe: [PATCH 1/2] ahci: Add PhyRdy Change control on actual LPM capability
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    On 2022/4/21 18:39, Damien Le Moal wrote:
    > On 4/21/22 18:43, Runa Guo-oc wrote:
    >> On some platform, when OS enables LPM by default (eg, min_power),
    >> then, PhyRdy Change cannot be detected if ahci supports no LPM.
    > Do you mean "...if the ahci adapter does not support LPM." ?

    Yes.

    > If that is what you mean, then min_power should not be set.

    Yes, I agree with you. But, as we know, link_power_management
    is a user policy which can be modified, if some users are not
    familiar with ahci spec, then the above case may happen.

    > Mario has patches to fix that.


    Hmm. How to patch this case ?

    >> In ahci spec, PhyRdy Change cannot coexist with LPM.
    >>
    >> Adds support to control this case on actual LPM capability.
    >>
    >> Signed-off-by: Runa Guo-oc <RunaGuo-oc@zhaoxin.com>
    >> ---
    >> drivers/ata/ahci.c | 9 +++++++++
    >> drivers/ata/libata-eh.c | 4 ++++
    >> include/linux/libata.h | 4 ++++
    >> 3 files changed, 17 insertions(+)
    >>
    >> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
    >> index 397dfd2..03f0cb3 100644
    >> --- a/drivers/ata/ahci.c
    >> +++ b/drivers/ata/ahci.c
    >> @@ -1870,6 +1870,15 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
    >> else
    >> dev_info(&pdev->dev, "SSS flag set, parallel bus scan disabled\n");
    >>
    >> + if (hpriv->cap & HOST_CAP_PART)
    >> + host->flags |= ATA_HOST_PART;
    >> +
    >> + if (hpriv->cap & HOST_CAP_SSC)
    >> + host->flags |= ATA_HOST_SSC;
    >> +
    >> + if (hpriv->cap2 & HOST_CAP2_SDS)
    >> + host->flags |= ATA_HOST_DEVSLP;
    >> +
    >> if (pi.flags & ATA_FLAG_EM)
    >> ahci_reset_em(host);
    >>
    >> diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
    >> index 3307ed4..05b1043 100644
    >> --- a/drivers/ata/libata-eh.c
    >> +++ b/drivers/ata/libata-eh.c
    >> @@ -3246,6 +3246,10 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
    >> unsigned int err_mask;
    >> int rc;
    >>
    >> + /* if controller does not support lpm, then sets no LPM flags*/
    >> + if (!(ap->host->flags & (ATA_HOST_PART | ATA_HOST_SSC | ATA_HOST_DEVSLP)))
    >> + link->flags |= ATA_LFLAG_NO_LPM;
    >> +
    >> /* if the link or host doesn't do LPM, noop */
    >> if (!IS_ENABLED(CONFIG_SATA_HOST) ||
    >> (link->flags & ATA_LFLAG_NO_LPM) || (ap && !ap->ops->set_lpm))
    >> diff --git a/include/linux/libata.h b/include/linux/libata.h
    >> index 732de90..7a243f4 100644
    >> --- a/include/linux/libata.h
    >> +++ b/include/linux/libata.h
    >> @@ -216,6 +216,10 @@ enum {
    >> ATA_HOST_PARALLEL_SCAN = (1 << 2), /* Ports on this host can be scanned in parallel */
    >> ATA_HOST_IGNORE_ATA = (1 << 3), /* Ignore ATA devices on this host. */
    >>
    >> + ATA_HOST_PART = (1 << 4), /* Host support partial.*/
    >> + ATA_HOST_SSC = (1 << 5), /* Host support slumber.*/
    >> + ATA_HOST_DEVSLP = (1 << 6), /* Host support devslp.*/
    >> +
    >> /* bits 24:31 of host->flags are reserved for LLD specific flags */
    >>
    >> /* various lengths of time */
    >

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