Re: [024/115] USB: prevent buggy hubs from crashing the USB stack

[Alan Stern]

On Wed, 23 Feb 2011, Alexander Holler wrote:

> Am 23.02.2011 09:06, schrieb Alexander Holler:
> > Am 16.02.2011 02:44, schrieb Greg KH:
> >> 2.6.32-longterm review patch. If anyone has any objections, please let
> >> us know.
> >
> > This patch killed the MUSB-host-functionality here (on a BeagleBoard).
> 
> Sorry, haven't seen at first, that the question was for 2.6.32. I had to 
> revert this patch for 2.6.37.1. Without the revert I've got endless 
> messages that the "parent hub has no TT".
> 
> I've configured musb in gadget-mode and I'm loading g_zero to use a 
> bt-dongle attached to the OTG-(MUSB-)port.
> 
> > Regards,
> >
> > Alexander

On Wed, 23 Feb 2011, Michael Jones wrote:

> Hi all,
> 
> My OMAP37 board started choking on my USB mouse when I updated from
> 2.6.37 to 2.6.38rc5.  I've tracked it down to commit
> d199c96d41d80a567493e12b8e96ea056a1350c1, "USB: prevent buggy hubs from
> crashing the USB stack."  If I revert this commit, my mouse works again.
> Otherwise, I get the message:
> 
> usb 1-1: new low speed USB device using musb-hdrc and address 33
> usb 1-1: parent hub has no TT
> 
> repeatedly (with 'address' incrementing).
> 
> I'm using the musb-hdrc driver for the OTG USB port in host mode.
> 
> some relevant config:
> CONFIG_USB_EHCI_HCD_OMAP=y
> CONFIG_USB_MUSB_HDRC=y
> CONFIG_USB_MUSB_OMAP2PLUS=y
> CONFIG_USB_MUSB_HOST=y
> CONFIG_USB_MUSB_HDRC_HCD=y
> CONFIG_USB_INVENTRA_DMA=y
> 
> # lsusb
> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
> Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
> 
> Any thoughts on how to get around this besides just reverting the
> commit?  Did anybody already encounter this?
> 
> thanks,
> Michael

In both cases, it appears that the problem is caused by the fact that 
the musb host-controller driver doesn't set the hcd->has_tt flag.

Felipe, you should know where it belongs.  It should be easy enough to 
add.

Alan Stern

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