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From:   Howard Yen <howardyen@google.com>
Date:   Thu, 28 Jan 2021 11:38:09 +0800
Message-ID: <CAJDAHvZ2CCm9tT+C=hNc_U1CaYJg3ZjifsYLik3UqfXwUm++Lg@mail.gmail.com>
Subject: Re: [PATCH 0/4] add xhci hooks for USB offload
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     Mathias Nyman <mathias.nyman@linux.intel.com>,
        Mathias Nyman <mathias.nyman@intel.com>, robh+dt@kernel.org,
        linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Tue, Jan 26, 2021 at 10:19 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Fri, Jan 22, 2021 at 05:32:58PM +0200, Mathias Nyman wrote:
> > On 20.1.2021 12.04, Howard Yen wrote:
> > > On Tue, Jan 19, 2021 at 8:47 PM Mathias Nyman <mathias.nyman@intel.com> wrote:
> > >>
> > >> On 19.1.2021 12.10, Howard Yen wrote:
> > >>> To let the xhci driver support USB offload, add hooks for vendor to have
> > >>> customized behavior for the initialization, memory allocation, irq work, and
> > >>> device context synchronization. Detail is in each patch commit message.
> > >>
> > >> Is this related to the usb audio sideband capability that was added to the xHCI specification?
> > >> If yes, then we should probably implement the generic parts first, and then add
> > >> the vendor specific hooks.
> > >>
> > >> -Mathias
> > >>
> > >>
> > >
> > > This is for offloading, no matter what type of offloading.
> > > I made the hooks generically and can be used for usb audio on the xhci
> > > which is not including the usb audio sideband capability.
> > >
> >
> > Ok, before adding hooks like this I think we need to see how they are used.
> > Do you have the rest of the patches that go on top of this series?
> >
> > Maybe it could make sense to use overrides for the functions in struct hc_driver
> > instead in some cases? There is support for that already.
>
> What overrides could be done for these changes?  At first glance that
> would seem to require a lot of duplicated code in whatever override
> happens to be needed.
>
> thanks,
>
> greg k-h

This patch series is all the changes for the offload hooks currently.

I thought about this, but if I tried to override the functions in
struct hc_driver, that'll need to
copy many code to the override function, and it won't follow the
latest change in the core
xhci driver.


- Howard