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Date: Fri, 1 Nov 2013 14:07:10 +0100
From: Joerg Roedel <joro@8bytes.org>
To: Peter Senna Tschudin <peter.senna@gmail.com>
Cc: iommu@lists.linux-foundation.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        Seiji Aguchi <seiji.aguchi@hds.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: VT-d and x2apic: broken resume after suspend to ram
Message-ID: <20131101130702.GA3348@8bytes.org>
References: <CA+MoWDqoBxuFhBsf_rVBT1C8=mwj02hXgPfuWnjY4yeVa-84cA@mail.gmail.com>
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Hi Peter,

On Fri, Nov 01, 2013 at 01:37:36PM +0100, Peter Senna Tschudin wrote:
> I have one notebook that is failing to resume after suspend to ram.
> I've filled a bug report back on the 2.6.41 days:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=787299
> 
> The issue is that trying to resume after suspending to ram freezes the
> computer. The resume starts well, but then it hangs.
> 
> Yesterday I found that this may be related to VT-d / x2apic. If I
> disable VT-d on the BIOS, suspend / resume works fine. If I enable
> VT-d and pass nox2apic as boot parameter to Kernel suspend and resume
> works fine. I would like some pointers to fix this issue. Can you help
> me?
> 
> Only when I have VT-d enabled, dmesg gives me additional output:
> [    0.023913] IOAPIC id 2 under DRHD base  0xfed91000 IOMMU 1
> [    0.024080] Enabled IRQ remapping in x2apic mode
> [    0.024081] Enabling x2apic
> [    0.024082] Enabled x2apic
> [    0.024087] Switched APIC routing to cluster x2apic.
> 
> The notebook is Toshiba R830-10p with i7-2620M.

Which kernels have you tried? Does it happen with all of them or is
there a kernel-version where this started?


	Joerg