linux-kernel - Re: [PATCH] Bluetooth: hci_bcm: Fix empty regulator supplies for Intel Macs

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Date:   Sat, 20 Apr 2019 10:10:14 +0200
From:   Dick Marinus <dick@...s.nl>
To:     linux-kernel@...r.kernel.org
Cc:     wens@...e.org
Subject: Re: [PATCH] Bluetooth: hci_bcm: Fix empty regulator supplies for
 Intel Macs

This fixes the issue for hanging at modprobe intel-lpss-pci on my
macbook pro 13,3 2016.

Error in dmesg:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000090

Thanks a lot!

Tested-by: Dick Marinus <dick@...s.nl>
> From: Chen-Yu Tsai <wens@...e.org>
> 
> The code path for Macs goes through bcm_apple_get_resources(), which
> skips over the code that sets up the regulator supplies. As a result,
> the call to regulator_bulk_enable() / regulator_bulk_disable() results
> in a NULL pointer dereference.
> 
> This was reported on the kernel.org Bugzilla, bug 202963.
> 
> Unbreak Broadcom Bluetooth support on Intel Macs by checking if the
> supplies were set up before enabling or disabling them.
> 
> The same does not need to be done for the clocks, as the common clock
> framework API checks for NULL pointers.
> 
> Fixes: 75d11676dccb ("Bluetooth: hci_bcm: Add support for regulator supplies")
> Cc: <stable@...r.kernel.org> # 5.0.x
> Signed-off-by: Chen-Yu Tsai <wens@...e.org>
> ---
> 
> I do not own a Mac, so this needs to be tested by someone else.
> 
> ---
>  drivers/bluetooth/hci_bcm.c | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
> index ddbe518c3e5b..b5d31d583d60 100644
> --- a/drivers/bluetooth/hci_bcm.c
> +++ b/drivers/bluetooth/hci_bcm.c
> @@ -228,9 +228,15 @@ static int bcm_gpio_set_power(struct bcm_device *dev, bool powered)
>  	int err;
>  
>  	if (powered && !dev->res_enabled) {
> -		err = regulator_bulk_enable(BCM_NUM_SUPPLIES, dev->supplies);
> -		if (err)
> -			return err;
> +		/* Intel Macs use bcm_apple_get_resources() and don't
> +		 * have regulator supplies configured.
> +		 */
> +		if (dev->supplies[0].supply) {
> +			err = regulator_bulk_enable(BCM_NUM_SUPPLIES,
> +						    dev->supplies);
> +			if (err)
> +				return err;
> +		}
>  
>  		/* LPO clock needs to be 32.768 kHz */
>  		err = clk_set_rate(dev->lpo_clk, 32768);
> @@ -259,7 +265,13 @@ static int bcm_gpio_set_power(struct bcm_device *dev, bool powered)
>  	if (!powered && dev->res_enabled) {
>  		clk_disable_unprepare(dev->txco_clk);
>  		clk_disable_unprepare(dev->lpo_clk);
> -		regulator_bulk_disable(BCM_NUM_SUPPLIES, dev->supplies);
> +
> +		/* Intel Macs use bcm_apple_get_resources() and don't
> +		 * have regulator supplies configured.
> +		 */
> +		if (dev->supplies[0].supply)
> +			regulator_bulk_disable(BCM_NUM_SUPPLIES,
> +					       dev->supplies);
>  	}
>  
>  	/* wait for device to power on and come out of reset */
> -- 
> 2.20.1