[xhci] Delay after (possibly) forcing port link state to RxDetect
authorMichael Brown <mcb30@ipxe.org>
Wed, 11 Feb 2015 11:18:35 +0000 (11:18 +0000)
committerMichael Brown <mcb30@ipxe.org>
Wed, 11 Feb 2015 11:18:35 +0000 (11:18 +0000)
commit32d20fdd7e09ba878f9409f8604e14d411c83abc
treeb0b575402dd68198029e6c1b0a903bd6db4103ce
parent1bb9e88ba068eb394153179c91cacab9a2383066
[xhci] Delay after (possibly) forcing port link state to RxDetect

Some xHCI controllers (observed with a Renesas Electronics PCIe USB3
card) seem to require a delay after forcing the link state of USB3
ports to RxDetect.  Omitting this delay causes strange behaviour
including system lockups.

Add an unconditional 20ms delay after writing the port link states.
This seems to be sufficient to avoid the problem.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
src/drivers/usb/xhci.c
src/drivers/usb/xhci.h