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Subject[patch 22/30] parport_pc: set properly the dma_mask for parport_pc device
2.6.27-stable review patch.  If anyone has any objections, please let us know.


From: FUJITA Tomonori <>

commit dfa7c4d869b7d3d37b70f1de856f2901b6ebfcf0 upstream.

parport_pc_probe_port() creates the own 'parport_pc' device if the
device argument is NULL. Then parport_pc_probe_port() doesn't
initialize the dma_mask and coherent_dma_mask of the device and calls
dma_alloc_coherent with it. dma_alloc_coherent fails because
dma_alloc_coherent() doesn't accept the uninitialized dma_mask:

Long ago, X86_32 and X86_64 had the own dma_alloc_coherent
implementations; X86_32 accepted a device having dma_mask that is not
initialized however X86_64 didn't. When we merged them, we chose to
prohibit a device having dma_mask that is not initialized. I think
that it's good to require drivers to set up dma_mask (and
coherent_dma_mask) properly if the drivers want DMA.

Signed-off-by: FUJITA Tomonori <>
Reported-by: Malcom Blaney <>
Tested-by: Malcom Blaney <>
Signed-off-by: Alan Cox <>
Acked-by: Jeff Garzik <>
Signed-off-by: Linus Torvalds <>
Signed-off-by: Greg Kroah-Hartman <>

drivers/parport/parport_pc.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/parport/parport_pc.c
+++ b/drivers/parport/parport_pc.c
@@ -2211,6 +2211,9 @@ struct parport *parport_pc_probe_port (u
if (IS_ERR(pdev))
return NULL;
dev = &pdev->dev;
+ dev->coherent_dma_mask = DMA_BIT_MASK(24);
+ dev->dma_mask = &dev->coherent_dma_mask;

ops = kmalloc(sizeof (struct parport_operations), GFP_KERNEL);

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