From: Ingo Molnar <mingo@elte.hu>
To: Marin Mitov <mitov@issp.bas.bg>, Dave Jones <davej@redhat.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
mingo@redhat.com, hpa@zytor.com
Subject: Re: [BUG] agpgart-amd64 not initialized in 2.6.33-rc2
Date: Mon, 28 Dec 2009 09:10:21 +0100 [thread overview]
Message-ID: <20091228081021.GD28652@elte.hu> (raw)
In-Reply-To: <200912280918.36067.mitov@issp.bas.bg>
* Marin Mitov <mitov@issp.bas.bg> wrote:
> On Monday 28 December 2009 08:37:33 am FUJITA Tomonori wrote:
> > On Sun, 27 Dec 2009 17:19:39 +0200
> > Marin Mitov <mitov@issp.bas.bg> 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.
Great! Fujita-san, mind sending a fully changelogged version of the patch with
Tested-by and your Signed-off-by?
Dave, do you want to push this fix to Linus, or should we do it via
x86/urgent?
Thanks,
Ingo
next prev parent reply other threads:[~2009-12-28 8:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-27 15:19 [BUG] agpgart-amd64 not initialized in 2.6.33-rc2 Marin Mitov
2009-12-28 6:37 ` FUJITA Tomonori
2009-12-28 7:18 ` Marin Mitov
2009-12-28 8:10 ` Ingo Molnar [this message]
2009-12-28 9:11 ` FUJITA Tomonori
2009-12-30 12:21 ` [tip:x86/urgent] x86/agp: Fix agp_amd64_init() initialization with CONFIG_GART_IOMMU enabled tip-bot for FUJITA Tomonori
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20091228081021.GD28652@elte.hu \
--to=mingo@elte.hu \
--cc=davej@redhat.com \
--cc=fujita.tomonori@lab.ntt.co.jp \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=mitov@issp.bas.bg \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).