Re: SATA link power management issues

Gabriele Mazzotta
2015-02-22T20:53:40Z

Hi,

It seems that the following patch prevents errors when the policy is
changed. Could anybody explain why?

Thanks,
Gabriele

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 61a9c07..38d39f7 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1708,7 +1708,10 @@ static void ahci_handle_port_interrupt(struct ata_port *ap,
status &= ~PORT_IRQ_BAD_PMP;

/* if LPM is enabled, PHYRDY doesn't mean anything */
- if (ap->link.lpm_policy > ATA_LPM_MAX_POWER) {
+ if (ap->link.lpm_policy > ATA_LPM_MAX_POWER ||
+ ap->link.flags & ATA_LFLAG_CHANGED) {
+ if (ap->link.flags & ATA_LFLAG_CHANGED)
+ ap->link.flags &= ~ATA_LFLAG_CHANGED;
status &= ~PORT_IRQ_PHYRDY;
ahci_scr_write(&ap->link, SCR_ERROR, SERR_PHYRDY_CHG);
}
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index d2029a4..e8f965c 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -3489,6 +3489,8 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
}
}

+ link->flags |= ATA_LFLAG_CHANGED;
+
return 0;

fail:
diff --git a/include/linux/libata.h b/include/linux/libata.h
index fc03efa..5abf5f2 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -205,6 +205,7 @@ enum {
ATA_LFLAG_SW_ACTIVITY = (1 << 7), /* keep activity stats */
ATA_LFLAG_NO_LPM = (1 << 8), /* disable LPM on this link */
ATA_LFLAG_RST_ONCE = (1 << 9), /* limit recovery to one reset */
+ ATA_LFLAG_CHANGED = (1 << 10),

/* struct ata_port flags */
ATA_FLAG_SLAVE_POSS = (1 << 0), /* host supports slave dev */