LKML Archive on
help / color / mirror / Atom feed
From: Kai-Heng Feng <>
	Kai-Heng Feng <>
Subject: [PATCH v2] USB: Don't enable LPM if it's already enabled
Date: Wed, 31 Oct 2018 13:52:09 +0800	[thread overview]
Message-ID: <> (raw)

USB Bluetooth controller QCA ROME (0cf3:e007) sometimes stops working
after S3:
[ 165.110742] Bluetooth: hci0: using NVM file: qca/nvm_usb_00000302.bin
[ 168.432065] Bluetooth: hci0: Failed to send body at 4 of 1953 (-110)

After some experiments, I found that disabling LPM can workaround the

On some platforms, the USB power is cut during S3, so the driver uses
reset-resume to resume the device. During port resume, LPM gets enabled
twice, by usb_reset_and_verify_device() and usb_port_resume().

So let's enable LPM for just once, as this solves the issue for the
device in question.

Signed-off-by: Kai-Heng Feng <>
 -  Check udev->usb2_hw_lpm_enabled before calling usb_port_resume().

 drivers/usb/core/hub.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index c6077d582d29..02fa574e98ce 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3523,7 +3523,8 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
 		hub_port_logical_disconnect(hub, port1);
 	} else  {
 		/* Try to enable USB2 hardware LPM */
-		if (udev->usb2_hw_lpm_capable == 1)
+		if (udev->usb2_hw_lpm_capable == 1 &&
+		    !udev->usb2_hw_lpm_enabled)
 			usb_set_usb2_hardware_lpm(udev, 1);
 		/* Try to enable USB3 LTM */

             reply	other threads:[~2018-10-31  5:52 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-31  5:52 Kai-Heng Feng [this message]
2018-11-23  6:03 ` Kai Heng Feng
2018-11-23 15:08 ` Greg KH

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \
    --subject='Re: [PATCH v2] USB: Don'\''t enable LPM if it'\''s already enabled' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).