libata: Add a drivers/ide style DMA disable
This is useful when debugging, handling problem systems, or for
distributions just to get the system installed so it can be sorted
out later.
This is a bit smarter than the old IDE one and lets you do
libata.dma=0 Disable all PATA DMA like old IDE
libata.dma=1 Disk DMA only
libata.dma=2 ATAPI DMA only
libata.dma=4 CF DMA only
(or combinations thereof - 0,1,3 being the useful ones I suspect)
(I've split CF as it seems to be a seperate case of pain and suffering
different to the others and caused by assorted PIO wired adapters etc)
Signed-off-by: Alan Cox <alan@redhat.com>
[edited to work on SATA too, changing name from 'pata_dma' to 'dma']
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 5532a65..1501d63 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -97,6 +97,10 @@
module_param_named(ignore_hpa, ata_ignore_hpa, int, 0644);
MODULE_PARM_DESC(ignore_hpa, "Ignore HPA limit (0=keep BIOS limits, 1=ignore limits, using full disk)");
+static int libata_dma_mask = ATA_DMA_MASK_ATA|ATA_DMA_MASK_ATAPI|ATA_DMA_MASK_CFA;
+module_param_named(dma, libata_dma_mask, int, 0444);
+MODULE_PARM_DESC(dma, "DMA enable/disable (0x1==ATA, 0x2==ATAPI, 0x4==CF)");
+
static int ata_probe_timeout = ATA_TMOUT_INTERNAL / HZ;
module_param(ata_probe_timeout, int, 0444);
MODULE_PARM_DESC(ata_probe_timeout, "Set ATA probing timeout (seconds)");
@@ -2917,14 +2921,27 @@
/* step 1: calculate xfer_mask */
ata_link_for_each_dev(dev, link) {
unsigned int pio_mask, dma_mask;
+ unsigned int mode_mask;
if (!ata_dev_enabled(dev))
continue;
+ mode_mask = ATA_DMA_MASK_ATA;
+ if (dev->class == ATA_DEV_ATAPI)
+ mode_mask = ATA_DMA_MASK_ATAPI;
+ else if (ata_id_is_cfa(dev->id))
+ mode_mask = ATA_DMA_MASK_CFA;
+
ata_dev_xfermask(dev);
pio_mask = ata_pack_xfermask(dev->pio_mask, 0, 0);
dma_mask = ata_pack_xfermask(0, dev->mwdma_mask, dev->udma_mask);
+
+ if (libata_dma_mask & mode_mask)
+ dma_mask = ata_pack_xfermask(0, dev->mwdma_mask, dev->udma_mask);
+ else
+ dma_mask = 0;
+
dev->pio_mode = ata_xfer_mask2mode(pio_mask);
dev->dma_mode = ata_xfer_mask2mode(dma_mask);