linux-kernel - Re: [PATCH 4/4] toshiba_bluetooth: Remove BT enable code from *

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Date:	Wed, 25 Mar 2015 10:50:42 -0700
From:	Darren Hart <dvhart@...radead.org>
To:	Azael Avalos <coproscefalo@...il.com>, Jes.Sorensen@...il.com
Cc:	platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] toshiba_bluetooth: Remove BT enable code from
 *_notify function

On Wed, Mar 18, 2015 at 01:12:59PM -0600, Azael Avalos wrote:
> Bug 93911 reported a broken handling of the BT device, causing the
> driver to get stuck in a loop enabling/disabling the device whenever
> the device is deactivated by the kill switch as follows:
> 
> 1. The user activated the kill switch, causing the system to generate
>    a 0x90 (status change) event and disabling the BT device.
> 2. The driver catches the event and re-enables the BT device.

It does? The toshiba_bluetooth_enable() call is supposed to exit silently if
BTST is not on. Is this check not working on some systems?

> 3. The system detects the device being activated, but since the kill
>    switch is activated, disables the BT device (again) and generates
>    a 0x90 event (again).
> 4. Repeat from 2.
> 
> This patch removes the toshiba_bluetooth_enable call from the
> toshiba_bluetooth_notify function, as we do not always need to
> re-activate the device everytime we receive an event, we need to act
> depending on the status of the BT device.
> 
> For now, we simply print the event received and the status of the BT
> device, so we can later add code to handle special circumstances
> depending on the status of the device.
> 
> Signed-off-by: Azael Avalos <coproscefalo@...il.com>
> ---
>  drivers/platform/x86/toshiba_bluetooth.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/toshiba_bluetooth.c b/drivers/platform/x86/toshiba_bluetooth.c
> index 0343d20..07edded 100644
> --- a/drivers/platform/x86/toshiba_bluetooth.c
> +++ b/drivers/platform/x86/toshiba_bluetooth.c
> @@ -2,6 +2,7 @@
>   * Toshiba Bluetooth Enable Driver
>   *
>   * Copyright (C) 2009 Jes Sorensen <Jes.Sorensen@...il.com>
> + * Copyright (C) 2015 Azael Avalos <coproscefalo@...il.com>
>   *
>   * Thanks to Matthew Garrett for background info on ACPI innards which
>   * normal people aren't meant to understand :-)
> @@ -25,6 +26,10 @@
>  #include <linux/types.h>
>  #include <linux/acpi.h>
>  
> +#define BT_KILLSWITCH_MASK	0x01
> +#define BT_PLUGGED_MASK		0x40
> +#define BT_POWER_MASK		0x80
> +
>  MODULE_AUTHOR("Jes Sorensen <Jes.Sorensen@...il.com>");
>  MODULE_DESCRIPTION("Toshiba Laptop ACPI Bluetooth Enable Driver");
>  MODULE_LICENSE("GPL");
> @@ -135,7 +140,20 @@ static int toshiba_bluetooth_disable(acpi_handle handle)
>  
>  static void toshiba_bt_rfkill_notify(struct acpi_device *device, u32 event)
>  {
> -	toshiba_bluetooth_enable(device->handle);
> +	int status;
> +
> +	pr_info("Received event %x\n", event);
> +
> +	/* Query the status of the Bluetooth device */
> +	status = toshiba_bluetooth_status(device->handle);
> +	if (status < 0)
> +		return;
> +
> +	pr_info("Switch status %x\n", status & BT_KILLSWITCH_MASK);
> +	pr_info("Power status %x\n", status & BT_POWER_MASK);
> +	pr_info("Plug status %x\n", status & BT_PLUGGED_MASK);

This seems a bit noisy for the info level as this information seems more aimed
at a developer working to complete the TODO below... debug seems more
appropriate.

> +
> +	/* TODO: Add event handling here depending on Bluetooth status */

Before if the RFKILL was disabled, this would have called
toshiba_bluetooth_enable() which would have checked BTST, found it on, and
enabled the device. In addition to killing the call to
toshiba_bluetooth_enable() when RFKILL is on, this also removes the call when
it's switched off.

I think I'm missing a path. Where does enable occur when the user turns the
radio back on now?


>  }
>  
>  #ifdef CONFIG_PM_SLEEP
> -- 
> 2.2.2
> 
> 

-- 
Darren Hart
Intel Open Source Technology Center
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