What is wrong with FreeBSD and USB Support
Hans Petter Selasky
hps at selasky.org
Mon Mar 6 11:41:38 UTC 2017
On 03/06/17 12:36, Markus Rechberger wrote:
> libusb20 - usb userspace interface - usb - roundtrip problem that
> causes this high latency.
If you are using an old FreeBSD kernel, more than two years old, there
was an issue where malloc() was used in the generic IOCTL path. This
piece has in later versions of FreeBSD been replace with a conditional
on-stack buffer. If you have this issue you should see high CPU usage on
one of the CPU cores while doing USB transfers fast.
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