From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932355AbWGLDGv (ORCPT ); Tue, 11 Jul 2006 23:06:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932357AbWGLDGv (ORCPT ); Tue, 11 Jul 2006 23:06:51 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:33230 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S932355AbWGLDGu (ORCPT ); Tue, 11 Jul 2006 23:06:50 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Andi Kleen Cc: Dave Olson , , Benjamin Herrenschmidt , discuss@x86-64.org Subject: Re: [PATCH 2/2] Initial generic hypertransport interrupt support. References: Date: Tue, 11 Jul 2006 21:05:54 -0600 In-Reply-To: (Andi Kleen's message of "12 Jul 2006 00:27:54 +0200") Message-ID: User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen writes: > ebiederm@xmission.com (Eric W. Biederman) writes: > >> This patch implements two functions ht_create_irq and ht_destroy_irq >> for use by drivers. Several other functions are implemented as helpers >> for arch specific irq_chip handlers. > > What do you want to use it for? Normally all HT configuration should be handled > by the BIOS and not messed with by the kernel. I don't believe this is a typical HT configuration as you are thinking of it. There is a hypertransport capability that implements a rough equivalent of a per device ioapic. It is quite similar to MSI but with a different register level interface. Since native hypertransport devices do not implement a pin emulation mode as native pci express devices do so if you want an interrupt you must support the native hypertransport method. The pathscale ipath-ht400 driver already in the kernel tree uses these and uses so an ugly hack to make work that broke in the last round of the msi cleanups. I also know of a driver under development for a device that uses these as well. So I want to use this so I can get irqs from native hypertransport devices. Eric