2022-03-21 21:36:25

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH v3 0/4] support USB offload feature

On Mon, Mar 21, 2022 at 06:24:09PM +0900, Jung Daehwan wrote:
> On Mon, Mar 21, 2022 at 10:14:23AM +0100, Greg Kroah-Hartman wrote:
> > On Mon, Mar 21, 2022 at 05:59:50PM +0900, Daehwan Jung wrote:
> > > This patchset is for USB offload feature, which makes Co-processor to use
> > > some memories of xhci. Especially it's useful for USB Audio scenario.
> > > Audio stream would get shortcut because Co-processor directly write/read
> > > data in xhci memories. It could get speed-up using faster memory like SRAM.
> > > That's why this gives vendors flexibilty of memory management.
> > > Several pathches have been merged in AOSP kernel(android12-5.10) and I put
> > > together and split into 3 patches. Plus let me add user(xhci-exynos)
> > > module to see how user could use it.
> > >
> > > To sum up, it's for providing xhci memories to Co-Processor.
> > > It would cover DCBAA, Device Context, Transfer Ring, Event Ring, ERST.
> > > It needs xhci hooks and to export some xhci symbols.
> > >
> > > Changes in v2 :
> > > - Fix commit message by adding Signed-off-by in each patch.
> > > - Fix conflict on latest.
> > >
> > > Changes in v3 :
> > > - Remove export symbols and xhci hooks which xhci-exynos don't need.
> > > - Modify commit message to clarify why it needs to export symbols.
> > > - Check compiling of xhci-exynos.
> >
> > As I asked for in the previous submission, you MUST have a user for
> > these hooks, otherwise we can not accept them (nor would you WANT us to
> > accept them). Please fix that up and add them to the next submission as
> > we can not do anything with this one.
> >
> > thanks,
> >
> > greg k-h
> >
>
> Hi greg,
>
> I've submitted the user(xhci-exynos) together on the last patch of the patchset.
> You can see xhci-exynos uses these hooks and symbols.
>
> [PATCH v3 4/4] usb: host: add xhci-exynos driver

Then this is not "offload" hooks at all. They are merely "support
another xhci platform driver, right?

I see a lot of exports and function hooks added, are they _ALL_ used by
the xhci driver? If so, please reword this series as it is not very
obvious at all what you are doing.

thanks,

greg k-h