Zerocopy should also be supported for ehci controllers. At least ehci and ohci controllers must be detected and ensured that everything still works on these devices.
Idea:
check if devices's dma_mask is > physical memory of the system. If yes, we can unconditionally use any memory from userspace. Otherwise we disable zerocopy completely for this device. This way we don't have to switch between copying and zerocopy based on the buffer we got from userspace. And newer controllers should support dma to the whole physical memory anyway.
Zerocopy should also be supported for ehci controllers. At least ehci and ohci controllers must be detected and ensured that everything still works on these devices.
Idea:
check if devices's dma_mask is > physical memory of the system. If yes, we can unconditionally use any memory from userspace. Otherwise we disable zerocopy completely for this device. This way we don't have to switch between copying and zerocopy based on the buffer we got from userspace. And newer controllers should support dma to the whole physical memory anyway.