Same thing for me, I have a Dell XPS 15z, with Intel and Nvidia GeForce GT 540M card, running Ubuntu 12.04. It's a dual-boot, using grub loader, Win7 on the other partition.
Everything was running fine until a couple of months back, when I installed a load of updates. Then one day I rebooted to Windows, did some work, then coming back to Ubuntu I got the ERROR:drm:intel_dsm_platform_mux_info] *ERROR* MUX INFO call failed. message after after grub, and then the machine hangs. After editing the grub loader command and setting acpi=off, it boots ok, although I lose the optirun capability, the multi-threading, and power management stuff. I also tried acpi=noirq i915.semaphores=1 after reading in on one of these forums...but this didn't work for me. An IT guy reinstalled drivers (instal the bumblebee and the nvidia- current driver recompiled from the official source deb), then it worked with acpi=noirq, optirun and multithreading etc. However on rebooting to Windows and back again, the problem reappeared, so back to setting acpi=off. I hope someone fixes this soon! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/913272 Title: drm:intel_dsm_platform_mux_info] *ERROR* MUX INFO call failed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/913272/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
