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Description of problem: Here at work we use HP 6730b laptops with the intel graphics drivers. When the machines boot they are fine until they actually go to use the X display, at which point X becomes choppy. Eventually the kernel module crashes with: Package: kernel Latest Crash: Fri 20 May 2011 11:12:32 AM Command: not_applicable Reason: WARNING: at drivers/pci/intel-iommu.c:1988 iommu_prepare_identity_map+0x153/0x198() Comment: None Bug Reports: After this happens, the X display becomes smooth and responsive. While this problem does not happen every time X is started, it happens the majority of the time. The workaround is to switch to another console (CTRL+F2 or whatever) and switch back. This usually either forces the crash or magically fixes the problem. Version-Release number of selected component (if applicable): Fedora release 14 (Laughlin) Linux barley.laptop.com 2.6.35.13-91.fc14.x86_64 #1 SMP Tue May 3 13:23:06 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux How reproducible: Boot the laptop. This happens consistently across all the 6730bs here running fedora. The ubuntu guys don't seem to have the problem. Our lone SuSE person does have the problem. Steps to Reproduce: 1. Start laptop. Display will become choppy at GDM 2. Switch to VT, switch back 3. If display is still choppy, repeat step 2 until the crash warning appears and display is happier. Tags: CommonBugs
Did you read the rest of that message? Your BIOS is broken; RMRR exceeds permitted address width Turn off virtualization in the BIOS or add "intel_iommu=off" to the kernel boot options.
Chuck, Thanks for the help. That is actually the full text of the error - I opened the ticket by choosing "copy to clipboard" from the crash report applet. If there's supposed to be more, it would help the users if it displayed the whole thing. ;) I tried it with "virtualization technologies" disabled in the BIOS and with the kernel parameter set and I get the same results. It just did it after setting intel_iommu=off. I will ask HP when they're updating their BIOS, this BIOS for this notebook (HP 6730b) is current. Googling for IOMMU set me in the right direction - looks like this is a common problem with Centrinos + HP. Thanks again, Joshua Knarr