2011-02-01 13:55:48

by FUJITA Tomonori

Subject: Re: b44 driver causes panic when using swiotlb

On Mon, 31 Jan 2011 10:54:12 -0500
Chuck Ebbert <[email protected]> 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;
}

2011-02-14 12:00:37

by FUJITA Tomonori

Subject: Re: b44 driver causes panic when using swiotlb

On Tue, 1 Feb 2011 22:54:56 +0900
FUJITA Tomonori <[email protected]> wrote:

> On Mon, 31 Jan 2011 10:54:12 -0500
> Chuck Ebbert <[email protected]> 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;
> }

Ping, any chance to try this?


Thanks,

2011-02-15 22:07:39

by Chuck Ebbert

Subject: Re: b44 driver causes panic when using swiotlb

On Mon, 14 Feb 2011 20:59:43 +0900
FUJITA Tomonori <[email protected]> wrote:

> > 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;
> > }
>
> Ping, any chance to try this?

The user who reported the bug tried it and says that it works.