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Subject: Re: Failure to shutdown/reboot with intel_iommu=on
To:     Joerg Roedel <jroedel@suse.de>,
        =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <uwe@kleine-koenig.org>
Cc:     linux-kernel@vger.kernel.org, rafael.j.wysocki@intel.com,
        tglx@linutronix.de, x86@kernel.org,
        Lu Baolu <baolu.lu@linux.intel.com>
References: <20200506144558.GA4019@taurus.defre.kleine-koenig.org>
 <20200508150734.GP8135@suse.de>
From:   Lenny Szubowicz <lszubowi@redhat.com>
Message-ID: <ff5eb4e2-89a3-57a5-c6d6-42bf743e5d16@redhat.com>
Date:   Mon, 11 May 2020 09:43:11 -0400
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On 5/8/20 11:07 AM, Joerg Roedel wrote:
> + Baolu, Maintainer of Intel IOMMU
> 
> Baolu, does that ring any bells?
> 
> On Wed, May 06, 2020 at 04:46:02PM +0200, Uwe Kleine-König wrote:
>> Hello,
>>
>> On my Lenovo T460p I cannot shutdown and reboot when the iommu is
>> enabled. This is using linux 5.2.7 as provided by Debian, 5.6.4 has the
>> same problem. Suspend/resume also fails; I suspect this is the same
>> issue.
>>
>> When requesting power off the kernel messages just end with:
>>
>> 	sd 0:0:0:0: [sda] Synchronizing SCSI cache
>> 	sd 0:0:0:0: [sda] Stopping disk
>> 	e1000e: EEE TX LPI TIMER: 00000011
>> 	ACPI: Preparing to enter system sleep state S5
>> 	reboot: Power down
>> 	acpi_power_off called
>>
>> (photo at https://www.kleine-koenig.org/tmp/uklsiommu.jpg in case I
>> mistyped something. Full dmesg and lspci -vvv at
>> https://www.kleine-koenig.org/tmp/uklsiommu.tar.gz with and without
>> iommu enabled.)
>>
>> With the iommu disabled (CONFIG_INTEL_IOMMU_DEFAULT_ON unset or
>> intel_iommu=off on cmdline) the machine just works as expected
>> (including working suspend/resume).
>>
>> I already talked to tglx on irc but unfortunately no new insights
>> resulted from that.
>>> Any ideas how to fix or continue debugging the issue?
>>
>> Best regards
>> Uwe
> 
> 

I suspect that you have TPM 2.x functionality enabled in the BIOS/firmware.

Unless you are actually using the TPM, try setting it to TPM 1.2 mode.
I've seen an incompatiblity on other Lenovo laptops between using the
IOMMU, TPM 2.x implementation in firmware, and shutdown/suspend.

                        -Lenny.