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From:   Ikjoon Jang <ikjn@chromium.org>
Date:   Fri, 8 Jan 2021 18:50:29 +0800
Message-ID: <CAATdQgAfRTxbzG4tJ-ftX7M6wrYFR6v+ji+-nSk_dTRTMXzXwQ@mail.gmail.com>
Subject: Re: [PATCH v5] usb: xhci-mtk: fix unreleased bandwidth data
To:     Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc:     "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>, linux-usb@vger.kernel.org,
        Tianping Fang <tianping.fang@mediatek.com>,
        Zhanyong Wang <zhanyong.wang@mediatek.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>
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On Fri, Jan 8, 2021 at 2:34 PM Chunfeng Yun <chunfeng.yun@mediatek.com> wrote:
>
> On Tue, 2020-12-29 at 14:24 +0800, Ikjoon Jang wrote:
> > xhci-mtk has hooks on add_endpoint() and drop_endpoint() from xhci
> > to handle its own sw bandwidth managements and stores bandwidth data
> > into internal table every time add_endpoint() is called,
> > so when bandwidth allocation fails at one endpoint, all earlier
> > allocation from the same interface could still remain at the table.
> If failed to add an endpoint, will cause failure of its interface
> config, then the other endpoints in the same interface will be dropped
> later? you mean some endpoints in an interface may fail but without
> affecting its function?

Yes, drop_endpoint() is called for a failed interface when set_interface()
fails to switch alt settings, but set_configuration() does not call
drop_endpoint().
TT data seems to remain allocated until a device gets removed.

>
> >
> > This patch adds two more hooks from check_bandwidth() and
> > reset_bandwidth(), and make mtk-xhci to releases all failed endpoints
> > from reset_bandwidth().
> >
> > Fixes: 08e469de87a2 ("usb: xhci-mtk: supports bandwidth scheduling with multi-TT")
> > Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
>