Re: [PATCH 2/2] usb: dwc3: drd: Fix lock-up on ID change during system suspend/resume

From: Felipe Balbi
Date: Mon Feb 12 2018 - 03:55:29 EST



Hi,

Roger Quadros <rogerq@xxxxxx> writes:
> Adding/removing host/gadget controller before .pm_complete()
> causes a lock-up. Let's prevent any dual-role state change
> between .pm_prepare() and .pm_complete() to fix this.
>
> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
> ---
> drivers/usb/dwc3/core.c | 31 +++++++++++++++++++++++++++++++
> drivers/usb/dwc3/core.h | 5 +++++
> drivers/usb/dwc3/drd.c | 10 ++++++----
> 3 files changed, 42 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 42379cc..85388dd 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1414,6 +1414,33 @@ static int dwc3_runtime_idle(struct device *dev)
> #endif /* CONFIG_PM */
>
> #ifdef CONFIG_PM_SLEEP
> +static int dwc3_prepare(struct device *dev)
> +{
> + struct dwc3 *dwc = dev_get_drvdata(dev);
> + unsigned long flags;
> +
> + if (dwc->dr_mode == USB_DR_MODE_OTG) {
> + spin_lock_irqsave(&dwc->lock, flags);
> + dwc->dr_keep_role = true;
> + spin_unlock_irqrestore(&dwc->lock, flags);
> + }
> +
> + return 0;
> +}
> +
> +static void dwc3_complete(struct device *dev)
> +{
> + struct dwc3 *dwc = dev_get_drvdata(dev);
> + unsigned long flags;
> +
> + if (dwc->dr_mode == USB_DR_MODE_OTG) {
> + spin_lock_irqsave(&dwc->lock, flags);
> + dwc->dr_keep_role = false;
> + spin_unlock_irqrestore(&dwc->lock, flags);
> + dwc3_drd_update(dwc);
> + }
> +}

wouldn't it be far easier to just disable OTG IRQ in prepare? and,
perhaps, also flush_work_sync() ?

--
balbi

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