Re: [PATCH 8/9] usb: dwc2/gadget: fix calls to phy control functions in suspend/resume code

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Hello,

On 2014-10-16 15:42, Felipe Balbi wrote:
On Thu, Oct 16, 2014 at 02:58:04PM +0200, Marek Szyprowski wrote:
This patch moves calls to phy enable/disable out of spinlock protected
blocks in device suspend/resume to fix incorrect caller context. Phy
related functions must not be called from atomic context.

Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
  drivers/usb/dwc2/gadget.c | 9 ++++++---
  1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index cdf417a7ae63..052b1a857291 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -3656,11 +3656,13 @@ static int s3c_hsotg_suspend(struct platform_device *pdev, pm_message_t state)
  			 hsotg->driver->driver.name);
spin_lock_irqsave(&hsotg->lock, flags);
+	s3c_hsotg_core_disconnect(hsotg);
  	s3c_hsotg_disconnect(hsotg);
-	s3c_hsotg_phy_disable(hsotg);
  	hsotg->gadget.speed = USB_SPEED_UNKNOWN;
  	spin_unlock_irqrestore(&hsotg->lock, flags);
+ s3c_hsotg_phy_disable(hsotg);
this is aching to have a locked version as well as an unlocked version.
Look at what you do here. There's a minor race when you release that
spinlock. By the time ->suspend() is called, IRQs are not yet disabled.

s3c_hsotg_core_disconnect() disconnects the udc hardware from the usb bus, so even
if the irq comes before s3c_hsotg_phy_disable(), nothing wrong happens, because the
driver state is already set to disconnected.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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