USB DMA memory Allocation

Sat Aug 3 00:16:57 UTC 2013

It seems to me that Intel ehci controller supports 64 DMA address lines
(HCCPARAMS register's 0 bit is set hardwired) then why do force DMA
allocation from [0 4GB] range.

I tried to enable 64 bit DMA allocations by modifying call to
'usb_dma_tag_setup' in usb_controller.c and usb_transfer.c but got a device
disconnect after we preallocated DMA memory for USB transfers.

Would be really great if someone could guide me on this.

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