USB: add quirk for devices with broken LPM
authorAlan Stern <stern@rowland.harvard.edu>
Thu, 10 Dec 2015 20:27:21 +0000 (15:27 -0500)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 23 Jan 2016 04:54:10 +0000 (20:54 -0800)
commit04db25a46b25ac5c29082a61f96067c8cd5984ad
treee4ec2bc35533c78ad9204ae79798945a6b2654aa
parentee10f5fe09105cc5495f00156f9a7914bbfa1c32
USB: add quirk for devices with broken LPM

commit ad87e03213b552a5c33d5e1e7a19a73768397010 upstream.

Some USB device / host controller combinations seem to have problems
with Link Power Management.  For example, Steinar found that his xHCI
controller wouldn't handle bandwidth calculations correctly for two
video cards simultaneously when LPM was enabled, even though the bus
had plenty of bandwidth available.

This patch introduces a new quirk flag for devices that should remain
disabled for LPM, and creates quirk entries for Steinar's devices.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Steinar H. Gunderson <sgunderson@bigfoot.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/core/hub.c
drivers/usb/core/quirks.c
include/linux/usb/quirks.h