ide-atapi: start DMA after issuing a packet command
Apparently¹, some ATAPI devices want to see the packet command first
before enabling DMA otherwise they simply hang indefinitely. Reorder the
two steps and start DMA only after having issued the command first.
[1] http://marc.info/?l=linux-kernel&m=123835520317235&w=2
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Reported-by: Michael Roth <mroth@nessie.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index d937e45..f591166 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -613,6 +613,10 @@
: ide_pc_intr),
timeout);
+ /* Send the actual packet */
+ if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
+ hwif->tp_ops->output_data(drive, NULL, rq->cmd, cmd_len);
+
/* Begin DMA, if necessary */
if (dev_is_idecd(drive)) {
if (drive->dma)
@@ -624,10 +628,6 @@
}
}
- /* Send the actual packet */
- if ((drive->atapi_flags & IDE_AFLAG_ZIP_DRIVE) == 0)
- hwif->tp_ops->output_data(drive, NULL, rq->cmd, cmd_len);
-
return ide_started;
}