Re: [usbip-devel] A strange problem happened.

[Takahiro H. <hir...@us...>]

Hi,


Yes. You need to support multiple virtual controllers.

- In vhci_init(), platform_device_register() registers a
non-plug-and-play device to the kernel.
This is corresponding to a virtual host controller.
You need to change here to call platform_device_register(pdev)
several times as needed.
So, pdev would be a member of a array.

- "the_controller" is also corresponding to a host controller. So, you
need more.
But, I think it can be removed by cleaning up code.
For instance, you can get it from pdev.
 usb_hcd = platform_get_drvdata(pdev);
 vhci_hcd = hcd_to_vhci(usb_hcd);


Regards,

Takahiro




2007/8/14, Lun Jiang <wo...@gm...>:
> Sorry I just found that I misread the stub part. Don't know how I got the
> impression.
> But the question still remains as if I should change "the_controller" into
> an array? Or is there a better way?
>
>
>  On 8/13/07, Lun Jiang <wo...@gm...> wrote:
> > Hi, thanks for the replies.
> > Actually we need to use usbip for a project which will map hundreds of
> small usb devices on a server like PC that is used to control them all.
> > I'm trying to alter the code to make usbip work for more virtual devices
> on the "client" side defined by usbip project(the side running usbip
> --attach <ip> <busid>)
> > I have followed the previous hint Takahiro gave out and ended up reading
> vhci.h and found the total manager of all virtual devices is
> > line 110:extern struct vhci_hcd *the_controller;
> > I wonder what is the relation of this with the "stub" mentioned in
> Takahiro's comment.
> > My understanding is that stub is the controller remaining on server side.
> > Because I need to expand the number of virtual usb devices on ONLY the
> client side, I wonder if I just need to change
> > the_controller
> > into an array to accommodate more?
> >
> > Lun
> >
> >
> >
> > On 8/2/07, Robert Leibl < rob...@gm...> wrote:
> > > On 02.Aug.07  , Takahiro Hirofuchi wrote:
> > > > Hello,
> > > >
> > > >
> > > > The maximum number of USB ports may be defined in the USB
> specification.
> > > > Please check it.  I think its value will not be large.
> > > > The Linux USB drivers are based on it.
> > >
> > > The maximum number of ports are defined in 'inlcude/linux/usb.h'
> > > Here is the relevant part of the file.
> > >
> > > /* This is arbitrary.
> > > * From USB 2.0 spec Table 11-13, offset 7, a hub can
> > > * have up to 255 ports. The most yet reported is 10.
> > > *
> > > * Current Wireless USB host hardware (Intel i1480 for example) allows
> > > * up to 22 devices to connect. Upcoming hardware might raise that
> > > * limit. Because the arrays need to add a bit for hub status data, we
> > > * do 31, so plus one evens out to four bytes.
> > > */
> > > #define USB_MAXCHILDREN         (31)
> > >
> > >
> > > I personally think this is a bit strange. Although the standard allows
> 255
> > > ports, it is set to 31 (so it will fit into 4 bytes).
> > >
> > >
> > > >
> > > > If you want to support more usbip connections concurrently,
> > > > please modify vhci_hcd driver code to support multiple root-hubs.
> > > > The current implementation initializes only one virtual root-hub,
> > > > which has only VHCI_NPORS virutal ports.
> > > > This modification will be done easiliy by adding small amount of code
> > > > into the initialization part of vhci_hcd.
> > >
> > > This change could even be made automatically. If on a connection of a
> device
> > > the number of used ports is e.g. (VHCI_NPORTS - 1), we register a new
> root
> > > hub.
> > > However, we would have to check, if the driver can support multiple
> hubs...
> > >
> > > >
> > > > Anyway, why do you need so many virtual ports?
> > > > You will not able to get good perfomance when many devices are
> connected.
> > > >
> > > > Regards,
> > > >
> > > > Takahrio
> > > >
> > > > [...]
> > >
> > > regards
> > > robert
> > >
> > > --
> > > If we don't believe in freedom of expression for people we despise, we
> > > don't believe in it at all.
> > >       -- Noam Chomsky (b. 1928)
> > >
> > >
> > >
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