Re: ehci_hcd map_single: unable to map unsafe buffer on a standard NSLU2
On Mon, Sep 10, 2007 at 07:05:25PM +0200, David & Anne-Sophie wrote:
> But, i try this driver on a PC with ubuntu and it works very well ?
Working on a PC does not mean the driver is correct. On a PC physical
addresses match the kernel's point of view in general, while on the arm
everything goes through interesting mappings, which make is essential
for the driver to correctly use readX/writeX calls along with ioremap
calls. Any attemps to directly access anything will fail on the arm
while it almost always works on a PC. Not sure quite how that might
impact a USB device, but even there the driver has to do DMA setup with
corrected addresses, which again is not necesary on a PC but is on the
arm.
--
Len Sorensen
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