libata: Ignore spurious PHY event on LPM policy change

When the LPM policy is set to ATA_LPM_MAX_POWER, the device might
generate a spurious PHY event that cuases errors on the link.
Ignore this event if it occured within 10s after the policy change.

The timeout was chosen observing that on a Dell XPS13 9333 these
spurious events can occur up to roughly 6s after the policy change.

Link: http://lkml.kernel.org/g/3352987.ugV1Ipy7Z5@xps13
Signed-off-by: Gabriele Mazzotta <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
Cc: [email protected]
This commit is contained in:
Gabriele Mazzotta 2015-04-25 19:52:37 +02:00 • committed by Tejun Heo
commit 09c5b4803a
3 changed files with 26 additions and 1 deletions

View file

@ -6766,8 +6766,21 @@ u32 ata_wait_register(struct ata_port *ap, void __iomem *reg, u32 mask, u32 val,
*/
bool sata_lpm_ignore_phy_events(struct ata_link *link)
{
unsigned long lpm_timeout = link->last_lpm_change +
msecs_to_jiffies(ATA_TMOUT_SPURIOUS_PHY);
/* if LPM is enabled, PHYRDY doesn't mean anything */
return !!(link->lpm_policy > ATA_LPM_MAX_POWER);
if (link->lpm_policy > ATA_LPM_MAX_POWER)
return true;
/* ignore the first PHY event after the LPM policy changed
* as it is might be spurious
*/
if ((link->flags & ATA_LFLAG_CHANGED) &&
time_before(jiffies, lpm_timeout))
return true;
return false;
}
EXPORT_SYMBOL_GPL(sata_lpm_ignore_phy_events);

View file

@ -3597,6 +3597,9 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
}
}
link->last_lpm_change = jiffies;
link->flags |= ATA_LFLAG_CHANGED;
return 0;
fail: