linux-kernel - Re: Qualcomm Atheros QCA61x4 keeps drawing 0.85 W despite Bluetooth being disable in GNOME

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Date:   Tue, 21 Nov 2023 11:23:07 -0500
From:   Alan Stern <stern@...land.harvard.edu>
To:     Paul Menzel <pmenzel@...gen.mpg.de>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-pm@...r.kernel.org,
        Hans de Goede <hdegoede@...hat.com>,
        Mike Jones <mike@...nes.io>,
        Rocky Liao <quic_rjliao@...cinc.com>
Subject: Re: Qualcomm Atheros QCA61x4 keeps drawing 0.85 W despite Bluetooth
 being disable in GNOME

On Mon, Nov 20, 2023 at 11:05:04PM +0100, Paul Menzel wrote:
> [Cc: +Rocky Liao as Qualcomm developer]

> Am 20.11.23 um 19:10 schrieb Alan Stern:
> > Again, nothing out of the ordinary.  Maybe dynamic debugging will give
> > us a clue.  Try doing this:
> > 
> > 	Unload the btusb module.
> > 
> > 	echo module usbcore +p >/sys/kernel/debug/dynamic_debug/control
> > 
> > 	Load the btusb module
> > 
> > 	Make sure that Bluetooth is turned off in Gnome
> > 
> > 	Wait a few seconds
> > 
> > 	echo module usbcore -p >/sys/kernel/debug/dynamic_debug/control
> > 
> > Then let's see what the dmesg log contains for that time period.
> 
> 
> ```
> $ sudo modprobe -r btusb
> $ sudo dmesg | tail -1
> [340309.272439] usbcore: deregistering interface driver btusb
> $ echo module usbcore +p | sudo tee /sys/kernel/debug/dynamic_debug/control
> module usbcore +p
> $ sudo modprobe btusb
> $ /sbin/rfkill
> ID TYPE      DEVICE      SOFT      HARD
>  1 wlan      phy0   unblocked unblocked
> 36 bluetooth hci0     blocked unblocked
> $ echo module usbcore -p | sudo tee /sys/kernel/debug/dynamic_debug/control
> module usbcore -p
> $ sudo modprobe -r btusb
> $ sudo dmesg | tail -1
> [340608.761313] usbcore: deregistering interface driver btusb
> $ sudo dmesg
> […]
> [340309.272439] usbcore: deregistering interface driver btusb
> [340560.326182] xhci_hcd 0000:00:14.0: hcd_pci_runtime_resume: 0
> [340560.326214] usb usb1: usb auto-resume
> [340560.326258] hub 1-0:1.0: hub_resume
> [340560.326381] usb usb1-port3: status 0107 change 0000
> [340560.326418] usb usb1-port4: status 0107 change 0000
> [340560.326451] usb usb1-port5: status 0507 change 0000
> [340560.326650] hub 1-0:1.0: state 7 ports 12 chg 0000 evt 0000
> [340560.326807] hub 1-0:1.0: state 7 ports 12 chg 0000 evt 0000
> [340560.373988] usb 1-3: usb auto-resume
> [340560.373998] hub 1-0:1.0: state 7 ports 12 chg 0000 evt 0008
> [340560.441936] usb 1-3: Waited 0ms for CONNECT
> [340560.441957] usb 1-3: finish reset-resume
> [340560.570940] usb 1-3: reset full-speed USB device number 2 using xhci_hcd

Those two lines are unexpected.  Why does the device need to be reset?
While the btusb module is loaded, does anything show up in
/sys/bus/usb/devices/1-3/quirks?

> > Also, please post the output from "lsusb -v" for the Bluetooth device.
> 
> ```
> $ sudo lsusb -d 0cf3:e300 -v
> 
> Bus 001 Device 002: ID 0cf3:e300 Qualcomm Atheros Communications QCA61x4
> Bluetooth 4.0
> Device Descriptor:
>   bLength                18
>   bDescriptorType         1
>   bcdUSB               2.01
>   bDeviceClass          224 Wireless
>   bDeviceSubClass         1 Radio Frequency
>   bDeviceProtocol         1 Bluetooth
>   bMaxPacketSize0        64
>   idVendor           0x0cf3 Qualcomm Atheros Communications
>   idProduct          0xe300 QCA61x4 Bluetooth 4.0
>   bcdDevice            0.01
>   iManufacturer           0
>   iProduct                0
>   iSerial                 0
>   bNumConfigurations      1
>   Configuration Descriptor:
>     bLength                 9
>     bDescriptorType         2
>     wTotalLength       0x00b1
>     bNumInterfaces          2
>     bConfigurationValue     1
>     iConfiguration          0
>     bmAttributes         0xe0
>       Self Powered
>       Remote Wakeup

That's what I was interested in.  The device does support remote wakeup.

> PPS: Looking through the commit log/history for `drivers/bluetooth/btusb.c`,
> I found commit 7ecacafc2406 (Bluetooth: btusb: Disable runtime suspend on
> Realtek devices) [1] authored on December 5th, 2019. This is for Realtek
> devices though, and not Qualcomm.

Furthermore the driver has changed considerably since 2019.  See
commits 8274db0776d1, 895915226a59, 7bd9fb058d77, and 34ec58b9fd1c.

Alan Stern