From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from qb-out-0506.google.com (qb-out-0506.google.com [72.14.204.235]) by ozlabs.org (Postfix) with ESMTP id 2C9DCDDE25 for ; Wed, 21 Jan 2009 06:17:53 +1100 (EST) Received: by qb-out-0506.google.com with SMTP id a16so1742498qbd.39 for ; Tue, 20 Jan 2009 11:17:51 -0800 (PST) Message-ID: Date: Tue, 20 Jan 2009 19:17:50 +0000 From: "Tom Arbuckle" To: linuxppc-dev@ozlabs.org Subject: Re: [RFC PATCH] "multifunc-device": fix IRQ assignment by also scanning dummy nodes In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 References: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, Did anybody pick up on this patch necessary to have OF understand so-called "multifunc-devices". I received no feedback on it. I note that the problem persists with 2.6.28.1 (although it was introduced by the PCI reorg for 2.6.20). File pci_32.c is unchanged in the latest release. Regards, Tom Arbuckle Homepage: http://www.ece.ul.ie/homepage/Tom_Arbuckle/ LinkedIn: http://www.linkedin.com/in/tomarbuckle ---------- Original message ---------- Kernel: 2.6.28; function: scan_OF_pci_childs; file: arch/powerpc/kernel/pci_32.c Quoting from line 206 : 'some OFs create a parent node "multifunc-device" as a fake root for all functions of a multi-function device. we go down them as well.' Function scan_OF_for_pci_dev (line 225) also needs to be taught about these dummy nodes to prevent misallocation/non-allocation of IRQs for this class of devices. Why RFC? I have chosen to scan all 'unusual' nodes as possible multifunc-devices. Is this too many? Bug seen when using a bt878 multimedia controller card on a G3 Powermac. This PCI card has separate audio and video nodes and was not being properly assigned interrupts. (Either 'cannot grab irq 0' or type of assigned interrupt wrt 'edge/level' was incorrect). Signed off by: Tom Arbuckle --- linux-2.6.28/arch/powerpc/kernel/pci_32.c.orig 2008-12-27 16:32:48.000000000 +0000 +++ linux-2.6.28/arch/powerpc/kernel/pci_32.c 2008-12-27 16:36:15.000000000 +0000 @@ -226,15 +226,21 @@ static struct device_node *scan_OF_for_p unsigned int devfn) { struct device_node *np; + struct device_node *np_sub = NULL; const u32 *reg; unsigned int psize; for_each_child_of_node(parent, np) { reg = of_get_property(np, "reg", &psize); - if (reg == NULL || psize < 4) - continue; - if (((reg[0] >> 8) & 0xff) == devfn) - return np; + if (reg && psize >= 4) { + if (((reg[0] >> 8) & 0xff) == devfn) + return np; + } + if (!strcmp(np->name, "multifunc-device")) { + np_sub = scan_OF_for_pci_dev(np, devfn); + if (np_sub) + return np_sub; + } } return NULL; }