Attachment 179366 Details for Bug 278533

[patch] atapi-dma-for-rw-only.patch

bug-332588_atapi-dma-for-rw-only.patch (text/plain), 1.15 KB, created by Tejun Heo on 2007-10-19 00:46:13 UTC

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Creator: Tejun Heo

Created: 2007-10-19 00:46:13 UTC

Size: 1.15 KB

patch

obsolete

>diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>index 68699b3..0ff981f 100644
>--- a/drivers/ata/libata-core.c
>+++ b/drivers/ata/libata-core.c
>@@ -52,6 +52,7 @@
> #include <scsi/scsi.h>
> #include <scsi/scsi_cmnd.h>
> #include <scsi/scsi_host.h>
>+#include <linux/cdrom.h>
> #include <linux/libata.h>
> #include <asm/io.h>
> #include <asm/semaphore.h>
>@@ -4446,12 +4447,26 @@ static void ata_fill_sg_dumb(struct ata_queued_cmd *qc)
> int ata_check_atapi_dma(struct ata_queued_cmd *qc)
> {
> 	struct ata_port *ap = qc->ap;
>-
>-	/* 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))
>+	struct scsi_cmnd *cmd = qc->scsicmd;
>+	u8 *cdb = cmd->cmnd;
>+
>+	/* some drives can only do ATAPI DMA on read/write */
>+	switch (cdb[0]) {
>+	case READ_10:
>+	case WRITE_10:
>+	case READ_12:
>+	case WRITE_12:
>+	case READ_6:
>+	case WRITE_6:
>+	case GPCMD_READ_CD:
>+	case GPCMD_READ_CD_MSF:
>+	case GPCMD_WRITE_AND_VERIFY_10:
>+		/* atapi dma maybe ok */
>+		break;
>+	default:
>+		/* turn off atapi dma */
> 		return 1;
>+	}
> 
> 	if (ap->ops->check_atapi_dma)
> 		return ap->ops->check_atapi_dma(qc);

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