Commit 5040ab67 authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
Browse files

libata: retry link resume if necessary 



Interestingly, when SIDPR is used in ata_piix, writes to DET in
SControl sometimes get ignored leading to detection failure.  Update
sata_link_resume() such that it reads back SControl after clearing DET
and retry if it's not clear.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarfengxiangjun <fengxiangjun@neusoft.com>
Reported-by: default avatarJim Faulkner <jfaulkne@ccs.neu.edu>
Cc: stable@kernel.org
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 0b67c743

drivers/ata/libata-core.c

+31 −7
Original line number Diff line number Diff line
@@ -3790,22 +3790,46 @@ int sata_link_debounce(struct ata_link *link, const unsigned long *params, 
int sata_link_resume(struct ata_link *link, const unsigned long *params,

		     unsigned long deadline)

{

	int tries = ATA_LINK_RESUME_TRIES;

	u32 scontrol, serror;

	int rc;



	if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol)))

		return rc;



	/*

	 * Writes to SControl sometimes get ignored under certain

	 * controllers (ata_piix SIDPR).  Make sure DET actually is

	 * cleared.

	 */

	do {

		scontrol = (scontrol & 0x0f0) | 0x300;



		if ((rc = sata_scr_write(link, SCR_CONTROL, scontrol)))

			return rc;



	/* Some PHYs react badly if SStatus is pounded immediately

	 * after resuming.  Delay 200ms before debouncing.

		/*

		 * Some PHYs react badly if SStatus is pounded

		 * immediately after resuming.  Delay 200ms before

		 * debouncing.

		 */

		msleep(200);



		/* is SControl restored correctly? */

		if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol)))

			return rc;

	} while ((scontrol & 0xf0f) != 0x300 && --tries);



	if ((scontrol & 0xf0f) != 0x300) {

		ata_link_printk(link, KERN_ERR,

				"failed to resume link (SControl %X)\n",

				scontrol);

		return 0;

	}



	if (tries < ATA_LINK_RESUME_TRIES)

		ata_link_printk(link, KERN_WARNING,

				"link resume succeeded after %d retries\n",

				ATA_LINK_RESUME_TRIES - tries);



	if ((rc = sata_link_debounce(link, params, deadline)))

		return rc;

include/linux/libata.h

+3 −0
Original line number Diff line number Diff line
@@ -354,6 +354,9 @@ enum { 
	/* max tries if error condition is still set after ->error_handler */

	ATA_EH_MAX_TRIES	= 5,



	/* sometimes resuming a link requires several retries */

	ATA_LINK_RESUME_TRIES	= 5,



	/* how hard are we gonna try to probe/recover devices */

	ATA_PROBE_MAX_TRIES	= 3,

	ATA_EH_DEV_TRIES	= 3,

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