Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 10 Oct 2003 14:47:10 +0400 | From | Ivan Kokshaysky <> | Subject | Re: USB and DMA on Alpha with 2.6.0-test7 |
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On Fri, Oct 10, 2003 at 11:22:06AM +0200, Måns Rullgård wrote: > Yesterday, I compiled 2.6.0-test7 for one of my Alpha boxes. I have > an AX8817X based USB ethernet adaptor connected to it (it's short on > PCI slots), so I compiled the usbnet module. When I loaded usbnet, I > got a BUG at include/asm-generic/dma-mapping.h:19. Apparently, DMA > setup only works with PCI here. How should this be fixed? It worked > with -test4, albeit slowly, for other reasons.
Well, the usage of dma_supported() in usbnet.c is wrong even for i386. USB device doesn't do DMA, it's USB controller what does. The driver should check dma_mask of the parent device instead, something like this:
// possible with some EHCI controllers if (*udev->dev->parent->dma_mask == 0xffffffffffffffffULL) net->features |= NETIF_F_HIGHDMA;
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