]> git.baikalelectronics.ru Git - kernel.git/commit
xhci: Prevent U1/U2 link pm states if exit latency is too long
authorMathias Nyman <mathias.nyman@linux.intel.com>
Wed, 5 Dec 2018 12:22:39 +0000 (14:22 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 6 Dec 2018 12:00:10 +0000 (13:00 +0100)
commit53898c377dba47ae55253244826e501e9ed58b3f
tree429aa5236402a508f3144670dda76beec5dd189a
parent66dd2a5ff6dfc489cce9a90e7b561ef11efe556b
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>
drivers/usb/host/xhci.c