ioat3: dca and raid operations are incompatible
RAID operations cause a system hang on platforms with DCA
(Direct-Cache-Access) enabled. So turn off RAID capabilities in this
case.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index 35d1e33..4f305f6 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -1117,6 +1117,7 @@
int __devinit ioat3_dma_probe(struct ioatdma_device *device, int dca)
{
struct pci_dev *pdev = device->pdev;
+ int dca_en = system_has_dca_enabled(pdev);
struct dma_device *dma;
struct dma_chan *c;
struct ioat_chan_common *chan;
@@ -1137,6 +1138,11 @@
dma->device_prep_dma_interrupt = ioat3_prep_interrupt_lock;
cap = readl(device->reg_base + IOAT_DMA_CAP_OFFSET);
+
+ /* dca is incompatible with raid operations */
+ if (dca_en && (cap & (IOAT_CAP_XOR|IOAT_CAP_PQ)))
+ cap &= ~(IOAT_CAP_XOR|IOAT_CAP_PQ);
+
if (cap & IOAT_CAP_XOR) {
is_raid_device = true;
dma->max_xor = 8;