[047/103] dmaengine: fix interrupt clearing for mv_xor

From: Greg KH
Date: Fri Oct 22 2010 - 15:11:53 EST


2.6.35-stable review patch. If anyone has any objections, please let us know.

------------------

From: Simon Guinot <sguinot@xxxxxxxxx>

commit cc60f8878eab892c03d06b10f389232b9b66bd83 upstream.

When using simultaneously the two DMA channels on a same engine, some
transfers are never completed. For example, an endless lock can occur
while writing heavily on a RAID5 array (with async-tx offload support
enabled).

Note that this issue can also be reproduced by using the DMA test
client.

On a same engine, the interrupt cause register is shared between two
DMA channels. This patch make sure that the cause bit is only cleared
for the requested channel.

Signed-off-by: Simon Guinot <sguinot@xxxxxxxxx>
Tested-by: Luc Saillard <luc@xxxxxxxxxxxx>
Acked-by: saeed bishara <saeed.bishara@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
drivers/dma/mv_xor.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -162,7 +162,7 @@ static int mv_is_err_intr(u32 intr_cause

static void mv_xor_device_clear_eoc_cause(struct mv_xor_chan *chan)
{
- u32 val = (1 << (1 + (chan->idx * 16)));
+ u32 val = ~(1 << (chan->idx * 16));
dev_dbg(chan->device->common.dev, "%s, val 0x%08x\n", __func__, val);
__raw_writel(val, XOR_INTR_CAUSE(chan));
}


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