Re: [PATCH] usb: musb: Fix locking errors for host only mode

[Bin Liu <b-liu-l0cyMroinI0@public.gmane.org>]

Hi,

On Thu, Aug 18, 2016 at 03:40:38PM -0700, Tony Lindgren wrote:
> If we have USB gadgets disabled and USB_MUSB_HOST set, we get
> errors "possible irq lock inverssion dependency detected"
> errors during boot.

On which platform was this issue found? I am trying to replicate the
issue on am335x, but have no luck yet - musb-hdrc does not load at all
when usb gadget support is disabled.

Regards,
-Bin.

> 
> Let's fix the issue by adding start_musb flag and start
> the controller after we're out of the spinlock protected
> section.
> 
> Reported-by: Ladislav Michl <ladis-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>
> Tested-by: Ladislav Michl <ladis-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>
> Signed-off-by: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
> ---
>  drivers/usb/musb/musb_virthub.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/musb/musb_virthub.c b/drivers/usb/musb/musb_virthub.c
> index 192248f..fe08e77 100644
> --- a/drivers/usb/musb/musb_virthub.c
> +++ b/drivers/usb/musb/musb_virthub.c
> @@ -290,6 +290,7 @@ int musb_hub_control(
>  	u32		temp;
>  	int		retval = 0;
>  	unsigned long	flags;
> +	bool		start_musb = false;
>  
>  	spin_lock_irqsave(&musb->lock, flags);
>  
> @@ -390,7 +391,7 @@ int musb_hub_control(
>  			 * logic relating to VBUS power-up.
>  			 */
>  			if (!hcd->self.is_b_host && musb_has_gadget(musb))
> -				musb_start(musb);
> +				start_musb = true;
>  			break;
>  		case USB_PORT_FEAT_RESET:
>  			musb_port_reset(musb, true);
> @@ -451,5 +452,9 @@ error:
>  		retval = -EPIPE;
>  	}
>  	spin_unlock_irqrestore(&musb->lock, flags);
> +
> +	if (start_musb)
> +		musb_start(musb);
> +
>  	return retval;
>  }
> -- 
> 2.8.1
> 
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