Skip to content
Commit 0472bf06 authored by Mathias Nyman's avatar Mathias Nyman Committed by Greg Kroah-Hartman
Browse files

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: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a7d57abc
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment