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SubjectRe: b44 driver causes panic when using swiotlb
From
On Mon, 31 Jan 2011 10:54:12 -0500
Chuck Ebbert <cebbert@redhat.com> wrote:

> The b44 driver is triggering this panic in swiotlb_map_page():
>
> if (!dma_capable(dev, dev_addr, size))
> panic("map_single: bounce buffer is not DMA'ble");
>
> The kernel log says the bounce buffers are at 0xdb400000, but b44 can
> only do DMA to the first 1GB of memory:

Can you try this? b44 has the own bouncing mechanism so if swiotlb
returns an error, the driver can allocate an appropriate buffer.

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index c47bbe1..93ca08b 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -686,8 +686,10 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
/*
* Ensure that the address returned is DMA'ble
*/
- if (!dma_capable(dev, dev_addr, size))
- panic("map_single: bounce buffer is not DMA'ble");
+ if (!dma_capable(dev, dev_addr, size)) {
+ swiotlb_tbl_unmap_single(dev, map, size, dir);
+ dev_addr = swiotlb_virt_to_bus(dev, io_tlb_overflow_buffer);
+ }

return dev_addr;
}

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