From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754324AbdBHNv1 (ORCPT ); Wed, 8 Feb 2017 08:51:27 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:56412 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752923AbdBHNvV (ORCPT ); Wed, 8 Feb 2017 08:51:21 -0500 Date: Wed, 8 Feb 2017 14:51:21 +0100 From: Greg Kroah-Hartman To: Alexander Stein Cc: Mathias Nyman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, "Wang, Yu" , "Li, Guanglei" , "Wu, Hao" Subject: Re: [PATCH v2 1/1] xhci: add USB2 test mode support Message-ID: <20170208135121.GB32594@kroah.com> References: <20170208134444.18369-1-alexander.stein@systec-electronic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170208134444.18369-1-alexander.stein@systec-electronic.com> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 08, 2017 at 02:44:44PM +0100, Alexander Stein wrote: > This patch adds support for USB2 test mode (Test_J, Test_K, > Test_SE0_NAK and Test_Packet) per XHCI spec 4.19.6. > > USB2 test mode is a required hardware feature for system integrators > validating their hardware according to USB spec, regarding signal > strength and stuff. It is purely a hardware test feature. > > Usually you need an oscilloscope and have to enable those test modes on > the hardware. This will send some specific test patterns on D+/D-. There > is no report available (in Linux itself) as it is purely externally > visible. Regular USB usage is not possible at that time. > Anyone (well access to e.g. /dev/bus/usb/001/001 provided) can use it by > sending appropriate USB_PORT_FEAT_TEST requests to the hub. > The same feature for ehci based hosts is already available at > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/host/ehci-hub.c#n1267 > > Signed-off-by: "Wang, Yu" > Signed-off-by: "Li, Guanglei" > Signed-off-by: "Wu, Hao" > Signed-off-by: Alexander Stein > --- > Changes in v2: > * Added additional info about USB2 test modes itself into commit message > * Add URL for same test mode feature on ehci hosts. Much nicer, thanks.