libata always uses PIO for ATAPI commands when the number of bytes to transfer isn't multiple of 16 but quantum DAT72 chokes on odd bytes PIO transfers. Implement a horkage to skip the mod16 check and apply it to the quantum device. This is reported by John Clark in the following thread. http://thread.gmane.org/gmane.linux.ide/34748 Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Cc: John Clark <clarkjc@xxxxxxxxxx> --- drivers/ata/libata-core.c | 4 +++- include/linux/libata.h | 2 ++ 2 files changed, 5 insertions(+), 1 deletions(-) diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 82af701..91b478f 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -4024,6 +4024,7 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = { /* Weird ATAPI devices */ { "TORiSAN DVD-ROM DRD-N216", NULL, ATA_HORKAGE_MAX_SEC_128 }, + { "QUANTUM DAT DAT72-000", NULL, ATA_HORKAGE_ATAPI_MOD16_DMA }, /* Devices we expect to fail diagnostics */ @@ -4444,7 +4445,8 @@ int atapi_check_dma(struct ata_queued_cmd *qc) /* Don't allow DMA if it isn't multiple of 16 bytes. Quite a * few ATAPI devices choke on such DMA requests. */ - if (unlikely(qc->nbytes & 15)) + if (!(qc->dev->horkage & ATA_HORKAGE_ATAPI_MOD16_DMA) && + unlikely(qc->nbytes & 15)) return 1; if (ap->ops->check_atapi_dma) diff --git a/include/linux/libata.h b/include/linux/libata.h index cc0ceaf..a2eb8f2 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -375,6 +375,8 @@ enum { ATA_HORKAGE_IVB = (1 << 8), /* cbl det validity bit bugs */ ATA_HORKAGE_STUCK_ERR = (1 << 9), /* stuck ERR on next PACKET */ ATA_HORKAGE_BRIDGE_OK = (1 << 10), /* no bridge limits */ + ATA_HORKAGE_ATAPI_MOD16_DMA = (1 << 11), /* use ATAPI DMA for commands + not multiple of 16 bytes */ /* DMA mask for user DMA control: User visible values; DO NOT renumber */ -- 1.5.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
