linux-kernel - Re: [PATCH] usb: musb: Force-disable pullup on shutdown

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Message-ID: <20190401182008.GL25852@uda0271908>
Date:   Mon, 1 Apr 2019 13:20:08 -0500
From:   Bin Liu <b-liu@...com>
To:     Paul Cercueil <paul@...pouillou.net>
CC:     <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <od@...c.me>
Subject: Re: [PATCH] usb: musb: Force-disable pullup on shutdown

On Mon, Apr 01, 2019 at 07:46:22PM +0200, Paul Cercueil wrote:
> 
> 
> Le lun. 1 avril 2019 à 19:17, Bin Liu <b-liu@...com> a écrit :
> >On Thu, Mar 21, 2019 at 03:42:46PM +0100, Paul Cercueil wrote:
> >> When the musb is shutdown, for instance when the driver is unloaded,
> >> force-disable the pullup. Otherwise, the host will still see
> >>the gadget
> >> device even after the shutdown.
> >
> >how would this happen?
> >
> >when musb-hdrc driver is unloaded, udc core removes the bound gadget
> >driver which calls musb_gadget_pullup() to disable the pullup.
> 
> I'm testing with the jz4740-musb driver. I don't unload the module (it's
> built-in) but unbind it from sysfs.

I did unbind too.

root@...35x-evm:/sys/bus/platform/drivers/musb-hdrc# echo musb-hdrc.0 > unbind

or unbind the glue driver:

root@...35x-evm:/sys/bus/platform/drivers/musb-dsps# echo 47401400.usb > unbind

musb_gadget_pullup() is called in both cases.

[ 3880.597014] [<bf444ab0>] (musb_gadget_pullup [musb_hdrc]) from [<bf402cbc>] (usb_gadget_disconnect+0x3c/0xf4 [udc_core])
[ 3880.607959] [<bf402cbc>] (usb_gadget_disconnect [udc_core]) from [<bf403b28>] (usb_gadget_remove_driver+0x4c/0x90 [udc_core])
[ 3880.619338] [<bf403b28>] (usb_gadget_remove_driver [udc_core]) from [<bf403d20>] (usb_del_gadget_udc+0x5c/0xc0 [udc_core])
[ 3880.630471] [<bf403d20>] (usb_del_gadget_udc [udc_core]) from [<bf439ff8>] (musb_remove+0x50/0x134 [musb_hdrc])
[ 3880.640648] [<bf439ff8>] (musb_remove [musb_hdrc]) from [<c05668cc>] (platform_drv_remove+0x28/0x48)
[ 3880.649831] [<c05668cc>] (platform_drv_remove) from [<c0564e3c>] (device_release_driver_internal+0xe4/0x1b4)
[ 3880.659708] [<c0564e3c>] (device_release_driver_internal) from [<c05633e4>] (bus_remove_device+0xe0/0x140)
[ 3880.669409] [<c05633e4>] (bus_remove_device) from [<c055f358>] (device_del+0x140/0x374)
[ 3880.677455] [<c055f358>] (device_del) from [<c0566ff0>] (platform_device_del.part.3+0x18/0x80)
[ 3880.686110] [<c0566ff0>] (platform_device_del.part.3) from [<c0567098>] (platform_device_unregister+0x24/0x30)
[ 3880.696170] [<c0567098>] (platform_device_unregister) from [<bf48c3e0>] (dsps_remove+0x1c/0x38 [musb_dsps])
[ 3880.706010] [<bf48c3e0>] (dsps_remove [musb_dsps]) from [<c05668cc>] (platform_drv_remove+0x28/0x48)
[ 3880.715190] [<c05668cc>] (platform_drv_remove) from [<c0564e3c>] (device_release_driver_internal+0xe4/0x1b4)
[ 3880.725065] [<c0564e3c>] (device_release_driver_internal) from [<c0562b2c>] (unbind_store+0x64/0xd8)
[ 3880.734253] [<c0562b2c>] (unbind_store) from [<c0350c58>] (kernfs_fop_write+0xf4/0x1cc)

Regards,
-Bin.