Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755400Ab1EWOVT (ORCPT ); Mon, 23 May 2011 10:21:19 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:32951 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754107Ab1EWOVR (ORCPT ); Mon, 23 May 2011 10:21:17 -0400 Date: Mon, 23 May 2011 10:20:49 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Felipe Balbi cc: Tanya Brokhman , , , , , "'open list'" Subject: Re: [PATCH v12 7/8] usb: Adding SuperSpeed support to dummy_hcd In-Reply-To: <20110523072142.GK3095@legolas.emea.dhcp.ti.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1758 Lines: 40 On Mon, 23 May 2011, Felipe Balbi wrote: > > > > +module_param_named(is_super_speed, mod_data.is_super_speed, bool, > > > > +S_IRUGO); MODULE_PARM_DESC(is_super_speed, "true to simulate > > > > +SuperSpeed connection"); > > > > > > you shouldn't need this. You should always enable SuperSpeed for this > > > driver. > > > > You mean I don't need the module parameter? IMO it's the best way to enable > > HS connection. If driver->speed=USB_SPEED_SUPER than dummy_hcd will try to > > enumerate the device on the SS root hub and if the gadget didn't provide SS > > descriptors - it will fail. Just as it happened before. Finding out from > > then it should hand the device over to the hs_hcd ;-) Meaning it would > disconnect the device, switch to hs_hcd and reconnect :-) No. That doesn't happen with real devices, so there's no reason dummy-hcd should do it. > > dummy_hcd that the enumeration failed is very complicated (if even possible) > > and I'm not sure that is the right thing to do... If you connect a real > > device over SS port to xHCI and the device doesn't provide SS descriptors - > > the enumeration fails and it's ok. But if you connect the same device to a > > HS port - it should work properly. This is what I tried to simulate with > > this parameter. > > it doesn't just fails, it gives the device over to the shared_hcd :-) It does not. xhci-hcd does not keep track of whether or not enumeration succeeds, and it doesn't do anything special when enumeration fails. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/