This patch adds the 10ms TRSTRCY delay between a reset and the following
Set Address command that is required by the USB 2.0 specification to the
EHCI root hub driver. The generic_hub driver that's used for XHCI and
external hubs already included this delay. This is such a glaring
violation of the spec that I'm really amazed how many USB 2.0 devices
we tested before seemed perfectly fine with responding to a Set Address
within 2 microframes of the reset...
It also increases the port reset hold delay by one millisecond to avoid
an ugly race condition on Tegra SoCs: they decided to time the 50ms
themselves instead of relying on the CPU to do it (fair enough), and to
automatically transition Port Reset to 0 and Port Enable to 1 after that
(bad idea). If the CPU's read-modify-write to clear Port Reset races
exactly with the host controller setting Port Enable, we may end up
clearing the bit again and going into the companion controller handoff
path later on. The added millisecond shouldn't cause any problems for
other host controllers and is not a big deal compared to other delays in
this code path.
BUG=chrome-os-partner:26749
TEST=Run several dozen reboot loops with The USB Stick of Death (TM) (a
blue Patriot XT 13fe:5200 with bcdDevice = 1.00), make sure it always
gets detected correctly.
Change-Id: Idd3329ae6d7e5e1c07a84a5475549b3459836b31
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/189872
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Reviewed-by: Jim Lin <jilin@nvidia.com>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
4deca38e9d