Re: b44 driver causes panic when using swiotlb

[FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>]

On Mon, 14 Feb 2011 17:41:54 +0100
Arkadiusz Mi^[$(D+\^[(Bkiewicz <arekm@maven.pl> wrote:

> FUJITA Tomonori wrote:
> 
> > On Tue, 1 Feb 2011 22:54:56 +0900
> > FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:
> > 
> >> 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;
> >>  }
> > 
> > Ping, any chance to try this?
> 
> Friend machine oopsed on network with b44 on 2.6.37, so we tried this patch 
> and network card was detected nicely and was actually usable. The oops 

Thanks for the confirmation.

> started to happen after he upgraded memory from 2GB to 4GB in his dell 
> vostro 1500 notebook.

Yeah, a system with 2GB memory doesn't use swiotlb so you don't hit
this bug.

Thanks,