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Date: Mon, 9 Oct 2017 11:03:43 -0500
From: Bin Liu <b-liu@ti.com>
To: Jonathan Liu <net147@gmail.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Maxime Ripard <maxime.ripard@free-electrons.com>,
        Chen-Yu Tsai <wens@csie.org>, <linux-usb@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <linux-sunxi@googlegroups.com>
Subject: Re: [PATCH] usb: musb: Check for host-mode using is_host_active() on
 reset interrupt
Message-ID: <20171009160343.GC32614@uda0271908>
Mail-Followup-To: Bin Liu <b-liu@ti.com>, Jonathan Liu <net147@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Maxime Ripard <maxime.ripard@free-electrons.com>,
        Chen-Yu Tsai <wens@csie.org>, linux-usb@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-sunxi@googlegroups.com
References: <20170927103522.30202-1-net147@gmail.com>
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Hi,

On Wed, Sep 27, 2017 at 08:35:22PM +1000, Jonathan Liu wrote:
> The sunxi musb has a bug where sometimes it will generate a babble
> error on device disconnect instead of a disconnect IRQ. When this
> happens the musb controller switches from host mode to device mode
> (it clears MUSB_DEVCTL_HM/MUSB_DEVCTL_SESSION and sets
> MUSB_DEVCTL_BDEVICE) and gets stuck in this state.
> 
> The babble error is misdetected as a bus reset because MUSB_DEVCTL_HM
> was cleared.
> 
> To fix this, use is_host_active() rather than (devctl & MUSB_DEVCTL_HM)
> to detect babble error so that sunxi musb babble recovery can handle it
> by restoring the mode. This information is provided by the driver logic
> and does not rely on register contents.
> 
> Cc: stable@vger.kernel.org # v4.1+
> Signed-off-by: Jonathan Liu <net147@gmail.com>

Applied. Thanks.
-Bin.