linux-kernel - Re: [PATCH 4.14 49/62] Bluetooth: btusb: Only check needs_reset

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Message-ID: <20180515170657.GA40373@rodete-desktop-imager.corp.google.com>
Date:   Tue, 15 May 2018 10:07:02 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Jeremy Cline <jcline@...hat.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Marcel Holtmann <marcel@...tmann.org>,
        Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH 4.14 49/62] Bluetooth: btusb: Only check
 needs_reset_resume DMI table for QCA rome chipsets

+ Guenter

On Mon, May 14, 2018 at 08:49:05AM +0200, Greg Kroah-Hartman wrote:
> 4.14-stable review patch.  If anyone has any objections, please let me know.

FYI, this backport is wrong. See below.

> ------------------
> 
> From: Hans de Goede <hdegoede@...hat.com>
> 
> commit fc54910280eb38bde923cdf0898e74687d8e6989 upstream.
> 
> Jeremy Cline correctly points out in rhbz#1514836 that a device where the
> QCA rome chipset needs the USB_QUIRK_RESET_RESUME quirk, may also ship
> with a different wifi/bt chipset in some configurations.
> 
> If that is the case then we are needlessly penalizing those other chipsets
> with a reset-resume quirk, typically causing 0.4W extra power use because
> this disables runtime-pm.
> 
> This commit moves the DMI table check to a btusb_check_needs_reset_resume()
> helper (so that we can easily also call it for other chipsets) and calls
> this new helper only for QCA_ROME chipsets for now.
> 
> BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1514836
> Cc: stable@...r.kernel.org
> Cc: Jeremy Cline <jcline@...hat.com>
> Suggested-by: Jeremy Cline <jcline@...hat.com>
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> Signed-off-by: Marcel Holtmann <marcel@...tmann.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> ---
>  drivers/bluetooth/btusb.c |   10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> --- a/drivers/bluetooth/btusb.c
> +++ b/drivers/bluetooth/btusb.c
> @@ -2902,6 +2902,12 @@ static int btusb_config_oob_wake(struct
>  }
>  #endif
>  
> +static void btusb_check_needs_reset_resume(struct usb_interface *intf)
> +{
> +	if (dmi_check_system(btusb_needs_reset_resume_table))
> +		interface_to_usbdev(intf)->quirks |= USB_QUIRK_RESET_RESUME;
> +}
> +
>  static int btusb_probe(struct usb_interface *intf,
>  		       const struct usb_device_id *id)
>  {
> @@ -3037,9 +3043,6 @@ static int btusb_probe(struct usb_interf
>  	hdev->send   = btusb_send_frame;
>  	hdev->notify = btusb_notify;
>  
> -	if (dmi_check_system(btusb_needs_reset_resume_table))
> -		interface_to_usbdev(intf)->quirks |= USB_QUIRK_RESET_RESUME;
> -
>  #ifdef CONFIG_PM
>  	err = btusb_config_oob_wake(hdev);
>  	if (err)
> @@ -3177,6 +3180,7 @@ static int btusb_probe(struct usb_interf
>  			hdev->setup = btusb_setup_csr;
>  
>  		set_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);
> +		btusb_check_needs_reset_resume(intf);

The original code puts this under the BTUSB_QCA_ROME section, but this
is getting placed under the BTUSB_CSR section.

Brian

>  	}
>  
>  	if (id->driver_info & BTUSB_SNIFFER) {