LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Kai-Heng Feng <kai.heng.feng@canonical.com>
To: gregkh@linuxfoundation.org
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Kai-Heng Feng <kai.heng.feng@canonical.com>
Subject: [PATCH] USB: Don't enable LPM if it's already enabled
Date: Tue, 30 Oct 2018 13:54:52 +0800	[thread overview]
Message-ID: <20181030055452.25969-1-kai.heng.feng@canonical.com> (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
issue.

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 <kai.heng.feng@canonical.com>
---
 drivers/usb/core/driver.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 53564386ed57..e11d2eac76b6 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1901,7 +1901,8 @@ int usb_set_usb2_hardware_lpm(struct usb_device *udev, int enable)
 	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
 	int ret = -EPERM;
 
-	if (enable && !udev->usb2_hw_lpm_allowed)
+	if (enable && !udev->usb2_hw_lpm_allowed ||
+	    udev->usb2_hw_lpm_enabled == enable)
 		return 0;
 
 	if (hcd->driver->set_usb2_hw_lpm) {
-- 
2.19.1


             reply	other threads:[~2018-10-30  5:55 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-30  5:54 Kai-Heng Feng [this message]
2018-10-30  6:16 ` kbuild test robot
2018-10-30  6:30 ` kbuild test robot
2018-10-30 14:24 ` Mathias Nyman
2018-10-30 15:00   ` Alan Stern
2018-10-30 15:07     ` Kai Heng Feng

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:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

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

  git send-email \
    --in-reply-to=20181030055452.25969-1-kai.heng.feng@canonical.com \
    --to=kai.heng.feng@canonical.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --subject='Re: [PATCH] USB: Don'\''t enable LPM if it'\''s already enabled' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* 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).