From: Alan Cox <[EMAIL PROTECTED]>
This will allow us to handle the tape drive problems Mark Lord reported
On Thu, 20 Sep 2007 22:42:17 +0100 Alan Cox <[EMAIL PROTECTED]> wrote:
> > According to information I have received, some ATA (and possibly ATAPI?)
> > devices intentionally return some data in these cases. In the case of
> > certain ATA devices, this returned data permits inspection of the
> > incorrected data.
>
> News to me. ATA like ST-506/ST-412 exposes error data on I/O READ/WRITE
> via the READ_BUFFER functionality but its basically useless without a lot
> of knowledge of the drive on anything post ST-412 era.
>
> Got any references ?
>
> The other possibility is to whine but accept it happens - on the other
> hand being lax about HSM errors is asking for corruption and it seems
> to be unique to this tape device.
>
> (and someone please don't tell me early pre ATAPI standard devices are
> trying to return the sense data in this way or I'll be ill)
Signed-off-by: Alan Cox <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
drivers/ata/libata-core.c | 9 +++++++--
include/linux/libata.h | 1 +
2 files changed, 8 insertions(+), 2 deletions(-)
diff -puN
drivers/ata/libata-core.c~libata-add-a-horkage-entry-for-drq-mishandling-atapi
drivers/ata/libata-core.c
---
a/drivers/ata/libata-core.c~libata-add-a-horkage-entry-for-drq-mishandling-atapi
+++ a/drivers/ata/libata-core.c
@@ -5240,8 +5240,13 @@ fsm_start:
if (unlikely(status & (ATA_ERR | ATA_DF))) {
ata_port_printk(ap, KERN_WARNING, "DRQ=1 with device "
"error, dev_stat 0x%X\n", status);
- qc->err_mask |= AC_ERR_HSM;
- ap->hsm_task_state = HSM_ST_ERR;
+
+ /* Some tape drives muck this up so don't explode
+ in those cases */
+ if (!(qc->dev->horkage & ATA_HORKAGE_DRQ)) {
+ qc->err_mask |= AC_ERR_HSM;
+ ap->hsm_task_state = HSM_ST_ERR;
+ }
goto fsm_start;
}
diff -puN
include/linux/libata.h~libata-add-a-horkage-entry-for-drq-mishandling-atapi
include/linux/libata.h
---
a/include/linux/libata.h~libata-add-a-horkage-entry-for-drq-mishandling-atapi
+++ a/include/linux/libata.h
@@ -338,6 +338,7 @@ enum {
ATA_HORKAGE_BROKEN_HPA = (1 << 4), /* Broken HPA */
ATA_HORKAGE_SKIP_PM = (1 << 5), /* Skip PM operations */
ATA_HORKAGE_HPA_SIZE = (1 << 6), /* native size off by one */
+ ATA_HORKAGE_DRQ = (1 << 7), /* Device forgets to clear DRQ
on error */
/* DMA mask for user DMA control: User visible values; DO NOT
renumber */
_
-
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