From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751710AbZL1HUh (ORCPT ); Mon, 28 Dec 2009 02:20:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751389AbZL1HUg (ORCPT ); Mon, 28 Dec 2009 02:20:36 -0500 Received: from mail.issp.bas.bg ([195.96.236.10]:37574 "EHLO mail.issp.bas.bg" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751251AbZL1HUf (ORCPT ); Mon, 28 Dec 2009 02:20:35 -0500 From: Marin Mitov Organization: Institute of Solid State Physics To: FUJITA Tomonori Subject: Re: [BUG] agpgart-amd64 not initialized in 2.6.33-rc2 Date: Mon, 28 Dec 2009 09:18:35 +0200 User-Agent: KMail/1.11.4 (Linux/2.6.33-rc2; KDE/4.2.4; x86_64; ; ) Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com References: <200912271719.39306.mitov@issp.bas.bg> <20091228153704Z.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: <20091228153704Z.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200912280918.36067.mitov@issp.bas.bg> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 28 December 2009 08:37:33 am FUJITA Tomonori wrote: > On Sun, 27 Dec 2009 17:19:39 +0200 > Marin Mitov wrote: > > > Hi all, > > > > Recently (2.6.33-rc2 kernel, x86_64, 4GB RAM) I found (in dmesg): > > > > [drm:mga_do_agp_dma_bootstrap] *ERROR* Unable to acquire AGP: -19 > > > > and there is no /dev/agpgart device on the machine while all is OK > > if booting 2.6.32.2. > > > > In both kernels I have: > > > > CONFIG_AGP=y > > CONFIG_AGP_AMD64=y > > > > CONFIG_GART_IOMMU=y > > > > but nevertheless dmesg shows: > > > > PCI-DMA: Using software bounce buffering for IO (SWIOTLB) > > > > due to quirks in via K8T800Pro host bridge. > > > > Looking for the reason I found that agp_amd64_init() appears in: > > > > #ifndef CONFIG_GART_IOMMU > > module_init(agp_amd64_init); > > module_exit(agp_amd64_cleanup); > > #endif > > > > /* so it is not invoked here due to CONFIG_GART_IOMMU=y */ > > > > and also appears in: > > > > arch/x86/kernel/pci-gart_64.c, function: gart_iommu_init() > > > > The last one is part of the struct x86_init_ops(struct x86_init_iommu, as a function pointer) > > only if gart-iommu is successfully detected, which is not the case here due to the quirk, > > so agp_amd64_init() is not invoked here neither. > > > > Sure, configuring the kernel without CONFIG_GART_IOMMU=y (which is not user selectable) > > > > should solve the problem, but usually users do not know about quirks, so it should > > work even as set here (and it works up to 2.6.32.2). I believe the bug is introduced > > with the changes in the order iommu detect/init works for 2.6.33. > > > > I am here for additional info/tests. > > Sorry about the regression. Does this works? Yes, it works for me, thank you. Marin Mitov > diff --git a/drivers/char/agp/amd64-agp.c b/drivers/char/agp/amd64-agp.c > index 2fb2e6c..5aa7a58 100644 > --- a/drivers/char/agp/amd64-agp.c > +++ b/drivers/char/agp/amd64-agp.c > @@ -725,9 +725,14 @@ static struct pci_driver agp_amd64_pci_driver = { > int __init agp_amd64_init(void) > { > int err = 0; > + static int done = 0; > > if (agp_off) > return -EINVAL; > + > + if (done++) > + return agp_bridges_found ? 0 : -ENODEV; > + > err = pci_register_driver(&agp_amd64_pci_driver); > if (err < 0) > return err; > @@ -771,12 +776,8 @@ static void __exit agp_amd64_cleanup(void) > pci_unregister_driver(&agp_amd64_pci_driver); > } > > -/* On AMD64 the PCI driver needs to initialize this driver early > - for the IOMMU, so it has to be called via a backdoor. */ > -#ifndef CONFIG_GART_IOMMU > module_init(agp_amd64_init); > module_exit(agp_amd64_cleanup); > -#endif > > MODULE_AUTHOR("Dave Jones , Andi Kleen"); > module_param(agp_try_unsupported, bool, 0); >