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Commit 09c5b480 authored by Gabriele Mazzotta's avatar Gabriele Mazzotta Committed by Tejun Heo
Browse files

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: default avatarGabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
parent 8393b811

drivers/ata/libata-core.c

+14 −1
Original line number Diff line number Diff line
@@ -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);

drivers/ata/libata-eh.c

+3 −0
Original line number Diff line number Diff line
@@ -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:

include/linux/libata.h

+9 −0
Original line number Diff line number Diff line
@@ -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])