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Cc:     baolu.lu@linux.intel.com,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: Subject: Re: [PATCH 1/1] iommu/vt-d: Skip TE disabling on quirky
 gfx dedicated iommu
To:     "Miao, Jun" <Jun.Miao@windriver.com>
References: <DM6PR11MB2587034DFBEDFB091CE9AAD58E790@DM6PR11MB2587.namprd11.prod.outlook.com>
From:   Lu Baolu <baolu.lu@linux.intel.com>
Message-ID: <0f4b6760-bb8f-ebd3-ab9d-4ecba819883c@linux.intel.com>
Date:   Wed, 22 Jul 2020 10:40:17 +0800
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Hi Jun,

On 7/22/20 10:26 AM, Miao, Jun wrote:
>>> Kernel panic - not syncing: DMAR hardware is malfunctioning
>>> CPU: 0 PID: 347 Comm: rtcwake Not tainted 5.4.0-yocto-standard #124
>>> Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4
>>> SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3162.A00.1904162000 04/16/2019
>>> Call Trace:
>>>    dump_stack+0x59/0x75
>>>    panic+0xff/0x2d4
>>>    iommu_disable_translation+0x88/0x90
>>>    iommu_suspend+0x12f/0x1b0
>>>    syscore_suspend+0x6c/0x220
>>>    suspend_devices_and_enter+0x313/0x840
>>>    pm_suspend+0x30d/0x390
>>>    state_store+0x82/0xf0
>>>    kobj_attr_store+0x12/0x20
>>>    sysfs_kf_write+0x3c/0x50
>>>    kernfs_fop_write+0x11d/0x190
>>>    __vfs_write+0x1b/0x40
>>>    vfs_write+0xc6/0x1d0
>>>    ksys_write+0x5e/0xe0
>>>    __x64_sys_write+0x1a/0x20
>>>    do_syscall_64+0x4d/0x150
>>>    entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>> RIP: 0033:0x7f97b8080113
>>> Code: 8b 15 81 bd 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00
>>> 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff
>>> 77 55 c3 0f 1f 40 00 48 83 ec 28 48 89 54 24 18
>>> RSP: 002b:00007ffcfa6f48b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
>>> RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f97b8080113
>>> RDX: 0000000000000004 RSI: 000055e7db03b700 RDI: 0000000000000004
>>> RBP: 000055e7db03b700 R08: 000055e7db03b700 R09: 0000000000000004
>>> R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000004
>>> R13: 000055e7db039380 R14: 0000000000000004 R15: 00007f97b814d700
>>> Kernel Offset: 0x38a00000 from 0xffffffff81000000 (relocation range:
>>> 0xffffffff80000000-0xffffffffbfffffff)
>>> ---[ end Kernel panic - not syncing: DMAR hardware is malfunctioning ]---
>

Do you mean that system hangs in iommu_disable_translation() without 
this fix.

> [S3 successfully with the patch]

And, this failure disappeared after you applied this fix?

Best regards,
baolu