On Tue, 7 Aug 2018, D. Ziesche wrote:
> Hello,
>
> I use a 'USB controller: PLX Technology, Inc. Device 3380 (rev ab)' for
> a custom usb gadget.
> With a more recent kernel (4.12+) the cpu hangs and the gadget device is
> not functioning at all.
>
> I used git-bisect and a basic test gadget from the kernel tree
> (tools/usb/ffs-aio-example/simple/device_app/aio_simple.c) to find the
> first
> bad commit: f16443a034c7aa359ddf6f0f9bc40d01ca31faea
> The bug still occurs with 4.18.0-rc7+.
>
> Steps to reproduce:
> 1. Compile and run the testtool
> 'tools/usb/ffs-aio-example/simple/device_app/aio_simple.c'
> 2. Connect with a host system
> 3. Disconnect from host system
> 4. Kernel suffers CPU lockups
>
> Shell output:
> ---
> $ ./a.out /dev/usb_gadget/aio_simple_gadget
> Event Bind
> Event Enable <- connected to host
> submit: in
> submit: out
> Event Suspend <- disconnected from host
> ---hangs--- <- Event Disable is missing
> ---
Yes, I see the problem. Commit f16443a034c7 was wrong in several
respects. One was fixed later in commit 7dbd8f4cabd9, but the problem
in net2280 remained.
I think the patch below (which is mostly a reversion of the relevant
parts of f16443a034c7) should fix it. Can you please test the patch
and let me know?
Alan Stern
Index: usb-4.x/drivers/usb/gadget/udc/net2280.c
===================================================================
--- usb-4.x.orig/drivers/usb/gadget/udc/net2280.c
+++ usb-4.x/drivers/usb/gadget/udc/net2280.c
@@ -1545,7 +1545,7 @@ static int net2280_pullup(struct usb_gad
writel(tmp | BIT(USB_DETECT_ENABLE), &dev->usb->usbctl);
} else {
writel(tmp & ~BIT(USB_DETECT_ENABLE), &dev->usb->usbctl);
- stop_activity(dev, dev->driver);
+ stop_activity(dev, NULL);
}
spin_unlock_irqrestore(&dev->lock, flags);
@@ -2466,8 +2466,11 @@ static void stop_activity(struct net2280
nuke(&dev->ep[i]);
/* report disconnect; the driver is already quiesced */
- if (driver)
+ if (driver) {
+ spin_unlock(&dev->lock);
driver->disconnect(&dev->gadget);
+ spin_lock(&dev->lock);
+ }
usb_reinit(dev);
}
@@ -3381,12 +3384,14 @@ static void handle_stat1_irqs(struct net
if (disconnect || reset) {
stop_activity(dev, dev->driver);
ep0_start(dev);
+ spin_unlock(&dev->lock);
if (reset)
usb_gadget_udc_reset
(&dev->gadget, dev->driver);
else
(dev->driver->disconnect)
(&dev->gadget);
+ spin_lock(&dev->lock);
return;
}
}
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