Re: Intel IOMMU on Dell Latitude E6400, Lenovo X200 & Dell PrecisionT5400

From: Oleg Orel
Date: Thu Jan 29 2009 - 20:28:59 EST

Yu, Fenghua wrote:
We had reported more details @ and

Look into
and find that:

wlan0: Failed to config new SSID to the low-level driver
BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
IP: [<ffffffff8037cf1f>] pci_find_upstream_pcie_bridge+0x1f/0xa0
[<ffffffff80386808>] get_domain_for_dev+0x58/0x620
[<ffffffff8029574d>] ? __alloc_pages_internal+0xed/0x4f0
[<ffffffff803870f8>] get_valid_domain_for_dev+0x18/0x150
[<ffffffff803875e7>] intel_map_single+0x47/0x160
[<ffffffff802b8726>] ? alloc_pages_current+0x76/0xf0
[<ffffffff8038777f>] intel_alloc_coherent+0x7f/0xb0

Wireless LAN could cause the NULL pointer access in get_domain_for_dev() which is IOMMU function.

As an experiment, could you disable wireless lan on your machine and try to boot IOMMU kernel?


I did it already yesterday. It didn't help. It fact I had disable all disableble devices, also, on T5400 when is failing as well, we do not have a wireless.

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