Hi Pratyush, Douglas Turner pointed me to this thread discussion http://www.spinics.net/lists/linux-usb/msg95103.html seems there is some issue to use new scheme enumeration with super speed devices Hi Sarah, Any comments will be appreciated Thanks, Aymen -----Original Message----- From: Pratyush Anand [mailto:pratyush.anand@xxxxxxxxx] Sent: mardi 26 novembre 2013 14:06 To: Aymen BOUATTAY; sarah.a.sharp@xxxxxxxxxxxxxxx Cc: linux-usb@xxxxxxxxxxxxxxx Subject: Re: Xhci Host not allowed to send get device desc at addr zero Hi Aymen On Tue, Nov 26, 2013 at 4:31 PM, Aymen BOUATTAY <aymen.bouattay@xxxxxx> wrote: > Hi, > > I'm using Kernel release 3.4 with an embedded xhci host controller > Seems USB core driver does not allow xhci controller to send a get > device descriptor at address zero As when a device is attached to the > root hub, usb core driver reset the device and if the link is > superspeed than do a set_address > > LeCroy Compliance test TD7.06 Data Payload Packet Framing Robustness > test script expects for get device descriptor at @ zero from host > > How to let xhci controller sending a get device descriptor command before setting an address to USB3 device ? It does not work because USE_NEW_SCHEME has not been enabled for super speed devices. I see following comment "An xHCI controller cannot send any packets to a device until a set address command successfully completes." in commit c6515272b858742962c1de0f3bf497a048b9abd7 Author: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> Date: Mon Apr 27 19:57:26 2009 -0700 USB: Support for addressing a USB device under xHCI Hi Sarah, But as per usb3.0 specs section 9.4.3 get descriptor should be allowed in default state. xhci specs is not very clear about it. xhci specs says "once a successful address device command has completed, system software can issue USB GET_DESCRIPTOR request through Default Control Endpoint to retrieve the USB Device, configuration, etc. descriptors from USB device." So, what if XHCI Software issues, SET ADDRESS(0) followed by GET DESC(Device). Regards Pratyush > > Thanks, > Aymen > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" > in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo > info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
