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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 <gabriele.mzt@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
This commit is contained in:
Gabriele Mazzotta 2015-04-25 19:52:37 +02:00 committed by Tejun Heo
parent 8393b811f3
commit 09c5b4803a
3 changed files with 26 additions and 1 deletions
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15
drivers/ata/libata-core.c
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);

3
drivers/ata/libata-eh.c
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:

9
include/linux/libata.h
View File

@ -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), /* LPM state changed on this link */
/* struct ata_port flags */
ATA_FLAG_SLAVE_POSS = (1 << 0), /* host supports slave dev */
@ -309,6 +310,12 @@ enum {
*/
ATA_TMOUT_PMP_SRST_WAIT = 5000,
/* When the LPM policy is set to ATA_LPM_MAX_POWER, there might
* be a spurious PHY event, so ignore the first PHY event that
* occurs within 10s after the policy change.
*/
ATA_TMOUT_SPURIOUS_PHY = 10000,
/* ATA bus states */
BUS_UNKNOWN = 0,
BUS_DMA = 1,
@ -788,6 +795,8 @@ struct ata_link {
struct ata_eh_context eh_context;
struct ata_device device[ATA_MAX_DEVICES];
unsigned long last_lpm_change; /* when last LPM change happened */
};
#define ATA_LINK_CLEAR_BEGIN offsetof(struct ata_link, active_tag)
#define ATA_LINK_CLEAR_END offsetof(struct ata_link, device[0])