Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268438AbUIBTqM (ORCPT ); Thu, 2 Sep 2004 15:46:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268474AbUIBTqM (ORCPT ); Thu, 2 Sep 2004 15:46:12 -0400 Received: from the-village.bc.nu ([81.2.110.252]:3473 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S268438AbUIBTp5 (ORCPT ); Thu, 2 Sep 2004 15:45:57 -0400 Subject: RE: [PATCH] Early USB handoff From: Alan Cox To: Aleksey Gorelov Cc: Pete Zaitcev , David Brownell , linux-usb-devel@lists.sourceforge.net, Linux Kernel Mailing List In-Reply-To: <5F106036E3D97448B673ED7AA8B2B6B30162E74A@scl-exch2k.phoenix.com> References: <5F106036E3D97448B673ED7AA8B2B6B30162E74A@scl-exch2k.phoenix.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1094150607.5645.26.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Thu, 02 Sep 2004 19:43:29 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1392 Lines: 31 On Iau, 2004-09-02 at 20:03, Aleksey Gorelov wrote: > Basically, in a case of legacy free BIOS, HC is not in > SMM mode, and USB IRQ is routed to PCI IRQ line and generates > interrupts. When this IRQ is enabled in PIC (by driver that > starts before HC driver), system is flooded with interrupts. The BIOS should not be leaving the device generating interrupts surely ? If that IRQ line ends up shared we are in trouble at boot time. > One solution is to reset HC, but it takes some time (at > least 50ms). I agree that it might duplicate SOME code in HC > driver, but HC init executes too late. Well, if handoff has > been done early, it might not be necessary to do the same in > HC driver. We don't always want to hand off. Some setups only work in USB legacy mode because of other bugs. Thats why the SMM fixup I did for E750x is triggered in specific cases. We can do such things with DMI table blacklists easily enough. My E750x fix already duplicates some of the hand off code so we are going to need it anyway and if there are more reasons for needing it then so be it. I happened to only need to fix UHCI thats all. Alan - 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/