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Subject: Re: [PATCH] usb: gadget: tegra-xudc: Fix idle suspend/resume
To:     Thierry Reding <thierry.reding@gmail.com>,
        Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     Nagarjuna Kristam <nkristam@nvidia.com>,
        <linux-usb@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20200417170537.2540914-1-thierry.reding@gmail.com>
From:   Jon Hunter <jonathanh@nvidia.com>
Message-ID: <60250b1f-f721-0631-59bf-513576473f44@nvidia.com>
Date:   Mon, 20 Apr 2020 15:32:41 +0100
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On 17/04/2020 18:05, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> When the XUDC device is idle (i.e. powergated), care must be taken not
> to access any registers because that would lead to a crash.
> 
> Move the call to tegra_xudc_device_mode_off() into the same conditional
> as the tegra_xudc_powergate() call to make sure we only force device
> mode off if the XUDC is actually powered up.
> 
> Fixes: 49db427232fe ("usb: gadget: Add UDC driver for tegra XUSB device mode controller")
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  drivers/usb/gadget/udc/tegra-xudc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/tegra-xudc.c b/drivers/usb/gadget/udc/tegra-xudc.c
> index 52a6add961f4..dfabc54cdc27 100644
> --- a/drivers/usb/gadget/udc/tegra-xudc.c
> +++ b/drivers/usb/gadget/udc/tegra-xudc.c
> @@ -3840,11 +3840,11 @@ static int __maybe_unused tegra_xudc_suspend(struct device *dev)
>  
>  	flush_work(&xudc->usb_role_sw_work);
>  
> -	/* Forcibly disconnect before powergating. */
> -	tegra_xudc_device_mode_off(xudc);
> -
> -	if (!pm_runtime_status_suspended(dev))
> +	if (!pm_runtime_status_suspended(dev)) {
> +		/* Forcibly disconnect before powergating. */
> +		tegra_xudc_device_mode_off(xudc);
>  		tegra_xudc_powergate(xudc);
> +	}
>  
>  	pm_runtime_disable(dev);


Acked-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>

Cheers
Jon

-- 
nvpublic