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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: Tejun Heo <tj@kernel.org>
Reported-by: fengxiangjun <fengxiangjun@neusoft.com>
Reported-by: Jim Faulkner <jfaulkne@ccs.neu.edu>
Cc: stable@kernel.org
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Tejun Heo 2010-01-11 11:14:44 +09:00 committed by Jeff Garzik
parent 0b67c7439f
commit 5040ab67a2
2 changed files with 35 additions and 8 deletions
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40
drivers/ata/libata-core.c
View File

@ -3790,21 +3790,45 @@ 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;
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.
/*
* Writes to SControl sometimes get ignored under certain
* controllers (ata_piix SIDPR). Make sure DET actually is
* cleared.
*/
msleep(200);
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.
*/
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;

3
include/linux/libata.h
View File

@ -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,