From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759982Ab3B1SK3 (ORCPT ); Thu, 28 Feb 2013 13:10:29 -0500 Received: from avon.wwwdotorg.org ([70.85.31.133]:34038 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754509Ab3B1SK2 (ORCPT ); Thu, 28 Feb 2013 13:10:28 -0500 Message-ID: <512F9D90.7090705@wwwdotorg.org> Date: Thu, 28 Feb 2013 11:10:24 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Alan Stern CC: Venu Byravarasu , gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: host: tegra: Reset Tegra USB controller before init References: In-Reply-To: X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/28/2013 08:09 AM, Alan Stern wrote: > On Thu, 28 Feb 2013, Venu Byravarasu wrote: > >> To clear any configurations made by U-Boot on Tegra USB controller, >> reset it before init in probe. >> >> Signed-off-by: Venu Byravarasu >> --- >> When U-Boot configures a Tegra USB controller in device mode and if the EHCI >> driver of kernel tries to set it to HOST mode, message "irq 52: nobody cared" >> appears and IRQ gets disabled. >> >> This issue was initially reported with: http://marc.info/?l=linux-tegra&m=136110175423601&w=2 >> >> To avoid such issues, due to configurations made by U-Boot driver, reset the >> Tegra USB controller, before configuring it by kernel. > > Does the Tegra platform use shared interrupts? If it does, what > happens if the IRQ is enabled and in use by another device before > ehci-tegra resets the USB controller? I believe there's a dedicated interrupt just for each individual controller.