The Linux Kernel has a bug on ARM/ARM64 systems where the USB CMA
memory is incorrectly mapped to userspace, breaking zerocopy.
When the Kernel allocates the memory, it clears it with memset().
If the mapping worked correctly, we should have zeroed out buffers,
if it doesn't, we get random Kernel memory. We now check for this,
and fall back to buffers in userspace if that's the case.
Signed-off-by: Steve Markgraf <steve@steve-m.de>
Steve Markgraf
f68bb2fa77