USB: Disable hub-initiated LPM for comms devices.

Hub-initiated LPM is not good for USB communications devices.  Comms
devices should be able to tell when their link can go into a lower power
state, because they know when an incoming transmission is finished.
Ideally, these devices would slam their links into a lower power state,
using the device-initiated LPM, after finishing the last packet of their
data transfer.

If we enable the idle timeouts for the parent hubs to enable
hub-initiated LPM, we will get a lot of useless LPM packets on the bus
as the devices reject LPM transitions when they're in the middle of
receiving data.  Worse, some devices might blindly accept the
hub-initiated LPM and power down their radios while they're in the
middle of receiving a transmission.

The Intel Windows folks are disabling hub-initiated LPM for all USB
communications devices under a xHCI USB 3.0 host.  In order to keep
the Linux behavior as close as possible to Windows, we need to do the
same in Linux.

Set the disable_hub_initiated_lpm flag for for all USB communications
drivers.  I know there aren't currently any USB 3.0 devices that
implement these class specifications, but we should be ready if they do.

Signed-off-by: Sarah Sharp <[email protected]>
Cc: Marcel Holtmann <[email protected]>
Cc: Gustavo Padovan <[email protected]>
Cc: Johan Hedberg <[email protected]>
Cc: Hansjoerg Lipp <[email protected]>
Cc: Tilman Schmidt <[email protected]>
Cc: Karsten Keil <[email protected]>
Cc: Peter Korsgaard <[email protected]>
Cc: Jan Dumon <[email protected]>
Cc: Petko Manolov <[email protected]>
Cc: Steve Glendinning <[email protected]>
Cc: "John W. Linville" <[email protected]>
Cc: Kalle Valo <[email protected]>
Cc: "Luis R. Rodriguez" <[email protected]>
Cc: Jouni Malinen <[email protected]>
Cc: Vasanthakumar Thiagarajan <[email protected]>
Cc: Senthil Balasubramanian <[email protected]>
Cc: Christian Lamparter <[email protected]>
Cc: Brett Rudley <[email protected]>
Cc: Roland Vossen <[email protected]>
Cc: Arend van Spriel <[email protected]>
Cc: "Franky (Zhenhui) Lin" <[email protected]>
Cc: Kan Yan <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Jussi Kivilinna <[email protected]>
Cc: Ivo van Doorn <[email protected]>
Cc: Gertjan van Wingerde <[email protected]>
Cc: Helmut Schaa <[email protected]>
Cc: Herton Ronaldo Krzesinski <[email protected]>
Cc: Hin-Tak Leung <[email protected]>
Cc: Larry Finger <[email protected]>
Cc: Chaoming Li <[email protected]>
Cc: Daniel Drake <[email protected]>
Cc: Ulrich Kunitz <[email protected]>
Signed-off-by: Sarah Sharp <[email protected]>

drivers/usb/class/cdc-acm.c

@@ -1664,6 +1664,7 @@ static struct usb_driver acm_driver = {
 #ifdef CONFIG_PM
 	.supports_autosuspend = 1,
 #endif
+	.disable_hub_initiated_lpm = 1,
 };
 
 /*

drivers/usb/class/cdc-wdm.c

@@ -1034,6 +1034,7 @@ static struct usb_driver wdm_driver = {
 	.post_reset =	wdm_post_reset,
 	.id_table =	wdm_ids,
 	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(wdm_driver);