linux-kernel - Re: [PATCH] usb: chipidea: host: Disable port power only if previously enabled

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Message-ID: <20191227014521.GB5283@b29397-desktop>
Date:   Fri, 27 Dec 2019 01:45:24 +0000
From:   Peter Chen <peter.chen@....com>
To:     Guenter Roeck <linux@...ck-us.net>
CC:     Peter Chen <peter.chen@...escale.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Michael Grzeschik <m.grzeschik@...gutronix.de>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: Re: [PATCH] usb: chipidea: host: Disable port power only if
 previously enabled

On 19-12-26 07:57:54, Guenter Roeck wrote:
> On shutdown, ehci_power_off() is called unconditionally to power off
> each port, even if it was never called to power on the port.
> For chipidea, this results in a call to ehci_ci_portpower() with a request
> to power off ports even if the port was never powered on.
> This results in the following warning from the regulator code.
> 
> WARNING: CPU: 0 PID: 182 at drivers/regulator/core.c:2596 _regulator_disable+0x1a8/0x210
> unbalanced disables for usb_otg2_vbus
> Modules linked in:
> CPU: 0 PID: 182 Comm: init Not tainted 5.4.6 #1
> Hardware name: Freescale i.MX7 Dual (Device Tree)
> [<c0313658>] (unwind_backtrace) from [<c030d698>] (show_stack+0x10/0x14)
> [<c030d698>] (show_stack) from [<c1133afc>] (dump_stack+0xe0/0x10c)
> [<c1133afc>] (dump_stack) from [<c0349098>] (__warn+0xf4/0x10c)
> [<c0349098>] (__warn) from [<c0349128>] (warn_slowpath_fmt+0x78/0xbc)
> [<c0349128>] (warn_slowpath_fmt) from [<c09f36ac>] (_regulator_disable+0x1a8/0x210)
> [<c09f36ac>] (_regulator_disable) from [<c09f374c>] (regulator_disable+0x38/0xe8)
> [<c09f374c>] (regulator_disable) from [<c0df7bac>] (ehci_ci_portpower+0x38/0xdc)
> [<c0df7bac>] (ehci_ci_portpower) from [<c0db4fa4>] (ehci_port_power+0x50/0xa4)
> [<c0db4fa4>] (ehci_port_power) from [<c0db5420>] (ehci_silence_controller+0x5c/0xc4)
> [<c0db5420>] (ehci_silence_controller) from [<c0db7644>] (ehci_stop+0x3c/0xcc)
> [<c0db7644>] (ehci_stop) from [<c0d5bdc4>] (usb_remove_hcd+0xe0/0x19c)
> [<c0d5bdc4>] (usb_remove_hcd) from [<c0df7638>] (host_stop+0x38/0xa8)
> [<c0df7638>] (host_stop) from [<c0df2f34>] (ci_hdrc_remove+0x44/0xe4)
> ...
> 
> Keeping track of the power enable state avoids the warning and traceback.
> 
> Fixes: c8679a2fb8dec ("usb: chipidea: host: add portpower override")
> Cc: Michael Grzeschik <m.grzeschik@...gutronix.de>
> Cc: Peter Chen <peter.chen@...escale.com>
> Cc: stable@...r.kernel.org
> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
> ---
>  drivers/usb/chipidea/host.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c
> index b45ceb91c735..48e4a5ca1835 100644
> --- a/drivers/usb/chipidea/host.c
> +++ b/drivers/usb/chipidea/host.c
> @@ -26,6 +26,7 @@ static int (*orig_bus_suspend)(struct usb_hcd *hcd);
>  
>  struct ehci_ci_priv {
>  	struct regulator *reg_vbus;
> +	bool enabled;
>  };
>  
>  static int ehci_ci_portpower(struct usb_hcd *hcd, int portnum, bool enable)
> @@ -37,7 +38,7 @@ static int ehci_ci_portpower(struct usb_hcd *hcd, int portnum, bool enable)
>  	int ret = 0;
>  	int port = HCS_N_PORTS(ehci->hcs_params);
>  
> -	if (priv->reg_vbus) {
> +	if (priv->reg_vbus && enable != priv->enabled) {
>  		if (port > 1) {
>  			dev_warn(dev,
>  				"Not support multi-port regulator control\n");
> @@ -53,6 +54,7 @@ static int ehci_ci_portpower(struct usb_hcd *hcd, int portnum, bool enable)
>  				enable ? "enable" : "disable", ret);
>  			return ret;
>  		}
> +		priv->enabled = enable;
>  	}
>  
>  	if (enable && (ci->platdata->phy_mode == USBPHY_INTERFACE_MODE_HSIC)) {
> -- 

Acked-by: Peter Chen <peter.chen@....com>

-- 

Thanks,
Peter Chen