diff options
| author | Tejun Heo <tj@kernel.org> | 2010-01-11 11:14:44 +0900 |
|---|---|---|
| committer | Jeff Garzik <jgarzik@redhat.com> | 2010-01-12 14:34:14 -0500 |
| commit | 5040ab67a2c6d5710ba497dc52a8f7035729d7b0 (patch) | |
| tree | dea2290e50111fde938bfcbb83de0377e7c4d94a | |
| parent | 0b67c7439fe2a5d76602de36854c88e2beab00b0 (diff) | |
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>
| -rw-r--r-- | drivers/ata/libata-core.c | 38 | ||||
| -rw-r--r-- | include/linux/libata.h | 3 |
2 files changed, 34 insertions, 7 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 22ff51bdbc8a..6728328f3bea 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -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; + /* + * 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. + */ + msleep(200); - if ((rc = sata_scr_write(link, SCR_CONTROL, scontrol))) - return rc; + /* is SControl restored correctly? */ + if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol))) + return rc; + } while ((scontrol & 0xf0f) != 0x300 && --tries); - /* Some PHYs react badly if SStatus is pounded immediately - * after resuming. Delay 200ms before debouncing. - */ - msleep(200); + 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; diff --git a/include/linux/libata.h b/include/linux/libata.h index 6a9c4ddd3d95..73112250862c 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -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, |