Re: 答复: [PATCH] USB: storage: fix Huawei mode switching regression

[Dan Williams <dcbw@redhat.com>]

On Wed, 2013-03-06 at 09:44 +0800, Greg KH wrote:
> On Wed, Mar 06, 2013 at 01:34:44AM +0000, Linlei (Lei Lin) wrote:
> > Hello Mork,
> > 
> > >> ------ Because in the embedded linux system, Android, or Chrome OS, 
> > >> etc. They don't integrate userspace usb_modeswitch utility for 
> > >> switching.
> > 
> > >Why not?  If they can upgrade the kernel, then they most certainly can install a userspace utility.
> > 
> > >There is no excuse for an embedded system to do this differently.
> > >Please see e.g. OpenWRT as an example of an embedded system doing this correctly.
> > 
> > But currently Android and Chrome OS has not integrated the
> > usb_modeswitch utility.
> 
> That is not a kernel problem.  I find it hard to believe that Chrome OS
> would not gladly accept code to resolve this issue, can't you put it
> into the modemmanager or whatever Chrome OS uses to handle their
> wireless modems?

They use ModemManager, and that's still not the best place to put
modeswitching.  The best place to modeswitch anything is usb_modeswitch.
No sense duplicating the functionality that usb_modeswitch already
supplies.

Dan

> 
> As for Android, sorry, you are on your own, you will just have to deal
> with the individual OEMs that are incorporating your hardware :(
> 
> > From a vendor's point of view, our purpose is to make our devices be
> > supported natively by those OS.
> 
> We have a solution, usb_modeswitch, any user should be using that.
> 
> > So we consider that add the switch function to the kernel resolves the
> > problem from the source.
> > Then this function will be inherited by Android & Chrome OS.
> 
> Don't circumvent horribly governed userspace projects by getting changes
> into the Linux kernel.  Go fix those projects instead.
> 
> Good luck,
> 
> greg k-h
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