Bug 219432

Summary:	Hard freeze on systems with Intel HD Graphics due to Intel IOMMU
Product:	Drivers	Reporter:	Jeffery To (jeffery.to)
Component:	IOMMU	Assignee:	drivers_iommu
Status:	NEEDINFO ---
Severity:	normal
Priority:	P3
Hardware:	Intel
OS:	Linux
Kernel Version:		Subsystem:
Regression:	No	Bisected commit-id:

Description Jeffery To 2024-10-27 23:47:41 UTC

I have a Lenovo ThinkPad x201 (Intel Core i5-540M) and an HP EliteBook 8440p (Intel Core i5-520M), both updated to the latest BIOS and with Ubuntu 24.04 installed (kernel 6.8.0).

Both hard freeze a few minutes after boot unless intel_iommu=igfx_off is set.

On the ThinkPad, without intel_iommu=igfx_off I get these messages in my logs:

DMAR: DRHD: handling fault status reg 3
DMAR: [DMA Write NO_PASID] Request device [00:02.0] fault addr 0xbb46c000 [fault reason 0x05] PTE Write access is not set

I haven't checked the logs on the EliteBook; I can do so if necessary.

According to Wikipedia[1], both have HD Graphics with the same device ID (0046). It would be great if IOMMU for graphics can be disabled for this chipset by the driver itself.

(These hard freezes are especially difficult/frustrating to diagnose when booting into a live CD/DVD/USB session to do a fresh install and the logs are lost after power off/reboot.)

[1]: https://en.wikipedia.org/wiki/List_of_Intel_graphics_processing_units#Gen5

Comment 1 Artem S. Tashkinov 2024-10-28 07:37:34 UTC

> Ubuntu 24.04 installed (kernel 6.8.0).

This kernel is not supported here.

Please try mainline 6.11.5 and confirm it's still the issue.

Comment 2 Jeffery To 2024-10-31 12:39:27 UTC

I've upgrade my ThinkPad to Ubuntu 24.10, and tested with:

* No intel_iommu parameter
* intel_iommu=on
* intel_iommu=igfx_off

with both the Ubuntu kernel (6.11.0-9-generic) and the mainline kernel they have available for testing[1] (6.11.0-061100-generic, built on 2024-09-15).

With both kernels, when intel_iommu=on and when the intel_iommu parameter is not specified, my system will slow down and freeze completely a few minutes after boot (it seems like the Ubuntu kernel will freeze slightly faster). With intel_iommu=igxfx_off my system behaves normally.

If it is really necessary I can build and test with 6.11.5. Please let me know if any other logs or debugging output would also help.

[1]: https://kernel.ubuntu.com/mainline/v6.11/amd64/

Comment 3 Jeffery To 2024-10-31 13:38:18 UTC

Forgot to add, I've experienced this issue since 5.15 when Intel IOMMU was enabled by default in Ubuntu 22.04[1][2]. I added intel_iommu=off to my grub config and moved on. I only decided to follow up on this issue when I recently tried to install Ubuntu 24.04 on another computer (the EliteBook) and encountered the same problem (when booting from a live USB to start the installation process).

[1]: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1973434
[2]: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1971699