Description of problem: I've got the follwing warning, after upgrading the kernel from rawhide: DMAR:Host address width 36 DMAR:DRHD (flags: 0x00000001)base: 0x0000000000000000 ------------[ cut here ]------------ WARNING: at drivers/pci/dmar.c:182 dmar_table_init+0x144/0x2bf() (Not tainted) Hardware name: HP Pavilion dv4 Your BIOS is broken; DMAR reported at address zero! BIOS vendor: Hewlett-Packard; Ver: F.24; Product Version: F.24 Modules linked in: Pid: 1, comm: swapper Not tainted 2.6.29.1-68.fc11.x86_64 #1 Call Trace: [<ffffffff8104aae7>] warn_slowpath+0xbc/0xf0 [<ffffffff8104b0bc>] ? release_console_sem+0x1c1/0x1f6 [<ffffffff8164576e>] ? pci_iommu_init+0x0/0x21 [<ffffffff813aa67e>] ? printk+0x41/0x43 [<ffffffff8164576e>] ? pci_iommu_init+0x0/0x21 [<ffffffff81661ba2>] dmar_table_init+0x144/0x2bf [<ffffffff8164576e>] ? pci_iommu_init+0x0/0x21 [<ffffffff816621ac>] intel_iommu_init+0x16/0x801 [<ffffffff8100e967>] ? xen_debugfs_create_u32_array+0x5f/0x6a [<ffffffff8164576e>] ? pci_iommu_init+0x0/0x21 [<ffffffff8164577c>] pci_iommu_init+0xe/0x21 [<ffffffff8100a05b>] do_one_initcall+0x5b/0x142 [<ffffffff81090a80>] ? register_irq_proc+0xb3/0xcf [<ffffffff81110000>] ? load_elf_binary+0xb91/0x165d [<ffffffff8163b750>] kernel_init+0x1d6/0x22e [<ffffffff810126ca>] child_rip+0xa/0x20 [<ffffffff81011fe7>] ? restore_args+0x0/0x30 [<ffffffff8163b57a>] ? kernel_init+0x0/0x22e [<ffffffff810126c0>] ? child_rip+0x0/0x20 ---[ end trace 4eaa2a86a8e2da22 ]--- Version-Release number of selected component (if applicable): kernel-2.6.29.1-68.fc11.x86_64 How reproducible: Every boot Additional info: Wasn't present in kernel-2.6.29.1-54.fc11.x86_64
It means just what it says (the warning was just added recently.) Report it to HP.
While I wait for the Linux loving guys at HP to fix it, is there a way to silence or ignore the warning? Or at least, make it not look like a kernel oops that is picked by kerneloops on my desktop?
(In reply to comment #2) > While I wait for the Linux loving guys at HP to fix it, is there a way to > silence or ignore the warning? Or at least, make it not look like a kernel oops > that is picked by kerneloops on my desktop? You can disable the iommu by adding 'intel_iommu=off' to the boot options.
Even with 'intel_iommu=off' in the boot options, confirmed by "Intel-IOMMU: disabled" in dmesg, the warning still appears. As far as I know, my CPU does not have any type of virtual machine support (I wish it had...). Current kernel: 2.6.29.5-191.fc11.x86_64 Any other workaround?
Getting the same error on a Dell. Did not get this error with the F11 kernel (only is F12).
I have an Acer Aspire 1410-2285 notebook and also have to add the intel_iommu=off to boot. I keep getting the same alert message as everyone else. Kernel warning: Your BIOS is broken; DMAR reported at address zero!
Same kind of error on HP notebook - I wonder if I disable intel_iomm if will have any effect on KVM? WARNING: at drivers/pci/dmar.c:598 check_zero_address+0x96/0x19b() (Not tainted) Hardware name: HP EliteBook 8530p Your BIOS is broken; DMAR reported at address zero! BIOS vendor: Hewlett-Packard; Ver: 68PDV Ver. F.0F; Product Version: F.0F Modules linked in: Pid: 0, comm: swapper Not tainted 2.6.31.12-174.2.3.fc12.x86_64 #1 Call Trace: [<ffffffff81051710>] warn_slowpath_common+0x84/0x9c [<ffffffff81423973>] ? _etext+0x0/0x1 [<ffffffff8105177f>] warn_slowpath_fmt+0x41/0x43 [<ffffffff8173e7fe>] check_zero_address+0x96/0x19b [<ffffffff81262181>] ? acpi_tb_verify_table+0x57/0x5c [<ffffffff812617df>] ? acpi_get_table_with_size+0x5a/0xb4 [<ffffffff81423973>] ? _etext+0x0/0x1 [<ffffffff8173e915>] detect_intel_iommu+0x12/0x8c [<ffffffff8171dbc3>] pci_iommu_alloc+0x5e/0x6c [<ffffffff8172d1a8>] mem_init+0x19/0x161 [<ffffffff81716be3>] start_kernel+0x20b/0x3fa [<ffffffff817162a1>] x86_64_start_reservations+0xac/0xb0 [<ffffffff8171639d>] x86_64_start_kernel+0xf8/0x107
BTW, I had this error but if I turn on VMX in the BIOS on my HP EliteBook 6930p it goes away.
Warnings are about BIOS bug not kernel.
same warning messages for my HP-DC7800 , CentOS 6.2 (2.6.32-279.el6.x86_64 #1 SMP) but it disappears after I switch on the virturalization option in BIOS (get into BIOS Security > System Security, and enable Virtualization Technology （VTx）and Virtualization Technology Directed I/O (VTd) After reboot, warning messages disappear.