Re: SATA link power management issues

Gabriele Mazzotta
2015-04-20T20:02:18Z

On Sunday 22 February 2015 21:53:35 Gabriele Mazzotta wrote:
> 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 */

Hi,

did anyone looked at the above change?

Thanks,
Gabriele