From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andreas Kemnade <andreas-cLv4Z9ELZ06ZuzBka8ofvg@public.gmane.org>
Subject: Re: [PATCHv2] usb: musb: Fix unbalanced platform_disable
Date: Mon, 19 Sep 2016 07:59:41 +0200
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To: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
Cc: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>, Bin Liu <b-liu-l0cyMroinI0@public.gmane.org>, Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>, Kishon Vijay Abraham I <kishon-l0cyMroinI0@public.gmane.org>, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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On Sun, 18 Sep 2016 08:19:02 -0700
Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> wrote:

> * Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org> [160918 05:13]:
> > 
> > FYI, while this patch allows me to boot my Panda board with NFS
> > over usbnet, it only works with cold boots. A warm reboot results
> > in the following warning, and no ethernet traffic going through.
> > The USB device is detected by the host though.
> 
> Yeah I noticed too that we still have issues. For example doing rmmod
> of omap2430 with gadget configured and connected will produce a
> hardirq-safe hardirq-unsafe lock order error. That also happens with
> reboot with gadget configured and connected.
> 
hmm, well, there is a musb_platform_disable() in musb_remove() which is
simply superfluous...
Some days ago we had a locking problem with musb_start() and moved
it out of the locked area. Maybe we could do also something similar
here.
 
> > I'm not sure whether this is a regression introduced by commit
> > a83e17d0f73b ("usb: musb: Improve PM runtime and phy handling for
> > 2430 glue layer") or an entirely different issue;
> ...
> > [    5.711303] [<c0872788>] (_raw_spin_unlock_irqrestore) from
> > [<c069b260>] (musb_gadget_queue+0x128/0x4ac)
> > [    5.711303] [<c069b260>] (musb_gadget_queue) from [<c06a9ae4>] 
> > (usb_ep_queue+0x38/0x1d4)
> > [    5.729766] [<c06a9ae4>] (usb_ep_queue) from [<c06aba40>] 
> > (rx_submit+0xc8/0x19c)
> > [    5.737548] [<c06aba40>] (rx_submit) from [<c06abb90>]
> > (rx_fill+0x7c/0xa0) [    5.737548] [<c06abb90>] (rx_fill) from
> > [<c06abbdc>] (eth_start+0x28/0x48) [    5.751983] [<c06abbdc>]
> > (eth_start) from [<c06abe7c>] (eth_open+0x6c/0x7c) [    5.751983]
> > [<c06abe7c>] (eth_open) from [<c0778c2c>] (__dev_open+0x9c/0x104)
> 
> This could be something else though. Care to email me your .config,
> maybe this is related to legacy g_ether being built in?
> 
> Anyways, please also give the following patch a try. The reason why we
> currently have no chance of getting musb_platform_enable/disable
> balanced is because we need to try to set the musb devctl session bit
> in various places and possibly retry too. So musb_start should really
> be called musb_try_start_session() or something.
> 
> So I think the only sane thing to do at this point is to revert the
> changes trying to enable/disable USB PHY from
> omap2430_musb_enable/disable. The other fixes are OK too as they get
> us a bit closer to making the platform glue calls balanced.
>
or to balance it there (in a better way as done by my first patch).

Regards,
Andreas
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