Mathias Nyman 0472bf06c6 xhci: Prevent U1/U2 link pm states if exit latency is too long
Don't allow USB3 U1 or U2 if the latency to wake up from the U-state
reaches the service interval for a periodic endpoint.

This is according to xhci 1.1 specification section 4.23.5.2 extra note:

"Software shall ensure that a device is prevented from entering a U-state
 where its worst case exit latency approaches the ESIT."

Allowing too long exit latencies for periodic endpoint confuses xHC
internal scheduling, and new devices may fail to enumerate with a
"Not enough bandwidth for new device state" error from the host.

Cc: <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-06 13:00:10 +01:00
..
2018-09-20 13:07:55 +02:00
2018-06-12 16:19:22 -07:00
2017-12-12 13:16:07 +01:00
2018-07-16 09:09:24 +02:00