Kernel/linux-next
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git synced 2025-01-08 15:04:45 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

libata: improve phantom device detection

Browse Source 
Currently libata uses four methods to detect device presence.

1. PHY status if available.
2. TF register R/W test (only promotes presence, never demotes)
3. device signature after reset
4. IDENTIFY failure detection in SFF state machine

Combination of the above works well in most cases but recently there
have been a few reports where a phantom device causes unnecessary
delay during probe.  In both cases, PHY status wasn't available.  In
one case, it passed #2 and #3 and failed IDENTIFY with ATA_ERR which
didn't qualify as #4.  The other failed #2 but as it passed #3 and #4,
it still caused failure.

In both cases, phantom device reported diagnostic failure, so these
cases can be safely worked around by considering any !ATA_DRQ IDENTIFY
failure as NODEV_HINT if diagnostic failure is set.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Tejun Heo 2008-11-13 10:04:46 +09:00 committed by Jeff Garzik
parent 58e20d8d34
commit 6a6b97d360
1 changed files with 11 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/ata/libata-sff.c
View File

@ -1227,10 +1227,19 @@ int ata_sff_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc,
/* ATA PIO protocol */
if (unlikely((status & ATA_DRQ) == 0)) {
/* handle BSY=0, DRQ=0 as error */
if (likely(status & (ATA_ERR | ATA_DF)))
if (likely(status & (ATA_ERR | ATA_DF))) {
/* device stops HSM for abort/error */
qc->err_mask |= AC_ERR_DEV;
else {
/* If diagnostic failed and this is
* IDENTIFY, it's likely a phantom
* device. Mark hint.
*/
if (qc->dev->horkage &
ATA_HORKAGE_DIAGNOSTIC)
qc->err_mask |=
AC_ERR_NODEV_HINT;
} else {
/* HSM violation. Let EH handle this.
* Phantom devices also trigger this
* condition. Mark hint.