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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2012-04-23 10:08:51 -0700
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2012-05-18 15:42:55 -0700
commite1f12eb6ba6f1e74007eb01ed26fad7c5239d62b (patch)
tree4c6753fc5091cd31b8cc0029e41f86f4f8c3b195 /drivers/usb/class
parente3567d2c15a7a8e2f992a5f7c7683453ca406d82 (diff)
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 <sarah.a.sharp@linux.intel.com> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: Hansjoerg Lipp <hjlipp@web.de> Cc: Tilman Schmidt <tilman@imap.cc> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Peter Korsgaard <jacmet@sunsite.dk> Cc: Jan Dumon <j.dumon@option.com> Cc: Petko Manolov <petkan@users.sourceforge.net> Cc: Steve Glendinning <steve.glendinning@smsc.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Kalle Valo <kvalo@qca.qualcomm.com> Cc: "Luis R. Rodriguez" <mcgrof@qca.qualcomm.com> Cc: Jouni Malinen <jouni@qca.qualcomm.com> Cc: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com> Cc: Senthil Balasubramanian <senthilb@qca.qualcomm.com> Cc: Christian Lamparter <chunkeey@googlemail.com> Cc: Brett Rudley <brudley@broadcom.com> Cc: Roland Vossen <rvossen@broadcom.com> Cc: Arend van Spriel <arend@broadcom.com> Cc: "Franky (Zhenhui) Lin" <frankyl@broadcom.com> Cc: Kan Yan <kanyan@broadcom.com> Cc: Dan Williams <dcbw@redhat.com> Cc: Jussi Kivilinna <jussi.kivilinna@mbnet.fi> Cc: Ivo van Doorn <IvDoorn@gmail.com> Cc: Gertjan van Wingerde <gwingerde@gmail.com> Cc: Helmut Schaa <helmut.schaa@googlemail.com> Cc: Herton Ronaldo Krzesinski <herton@canonical.com> Cc: Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Larry Finger <Larry.Finger@lwfinger.net> Cc: Chaoming Li <chaoming_li@realsil.com.cn> Cc: Daniel Drake <dsd@gentoo.org> Cc: Ulrich Kunitz <kune@deine-taler.de> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Diffstat (limited to 'drivers/usb/class')
-rw-r--r--drivers/usb/class/cdc-acm.c1
-rw-r--r--drivers/usb/class/cdc-wdm.c1
2 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index b32ccb461019..f2a120eea9d4 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/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,
};
/*
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 631bb952d0f6..ea8b304f0e85 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/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);