linux-kernel - [REGRESSION] resume takes 10s longer due to e1b6eb3 (Bluetooth: Increase HCI reset timeout ...)

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Message-ID: <20111118184017.GA5052@nomi.cz>
Date:	Fri, 18 Nov 2011 19:40:17 +0100
From:	Tomáš Janoušek <tomi@...i.cz>
To:	Szymon Janc <szymon@...c.net.pl>,
	"Gustavo F. Padovan" <padovan@...fusion.mobi>,
	Marcel Holtmann <marcel@...tmann.org>,
	linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [REGRESSION] resume takes 10s longer due to e1b6eb3 (Bluetooth:
	Increase HCI reset timeout ...)

Hello,

while testing the 3.2-rc kernel, I experienced that resume takes 10 seconds
more than usual, and bisected this to be caused by e1b6eb3 (Bluetooth:
Increase HCI reset timeout in hci_dev_do_close).

My hardware is Lenovo ThinkPad T420, model number 4178-A3G, with a Broadcom
Bluetooth adapter (I'm attaching the relevant part of lsusb).

The relevant portion of dmesg is:
[   76.502818] usb 1-1.4: reset full-speed USB device number 4 using ehci_hcd
[   76.588225] btusb 1-1.4:1.0: no reset_resume for driver btusb?
[   76.591870] btusb 1-1.4:1.1: no reset_resume for driver btusb?
[   86.565269] PM: resume of devices complete after 10486.220 msecs

My resume scripts did contain a hciconfig hci0 down followed by up, because
on my previous notebook (and the kernel I used at the time) it was needed for
BT to work after suspend. On this hardware, however, none of that is needed.
Bluetooth after suspend works regardless of whether that patch is applied or
not, and I believe it would wait indefinitely if given large enough timeout.

Aside from reverting the patch, doing the following before suspend also works
around the issue:
    echo disable > /proc/acpi/ibm/bluetooth

Kind regards,
-- 
Tomáš Janoušek, a.k.a. Liskni_si, http://work.lisk.in/

View attachment "bt.txt" of type "text/plain" (11013 bytes)