** Description changed: I found what I believe is a regression on my Gateway ne570 laptop. It was running mythbuntu 14.04 LTS and ubuntu 15.04 releases quite well. But when I installed ubuntu 16.04 LTS, I found dmesg and kern.log were filling with messages like this: Jul 10 17:01:10 buus-ne570 kernel: [ 57.741630] ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341) Jul 10 17:01:10 buus-ne570 kernel: [ 57.803775] ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341) Jul 10 17:01:10 buus-ne570 kernel: [ 57.866294] ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341) Jul 10 17:01:10 buus-ne570 kernel: [ 57.928403] ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341) These messages would be repeated several times a second, and then pause for several seconds, then start again. I believe they are the cause of more sluggish behavior than with the older *Buntu releases. I followed the instructions here: https://wiki.ubuntu.com/Kernel/KernelBisection - which lead me to doing "git bisect" on the linux-stable kernel. The result lead me to this commit: + which lead me to doing "git bisect" on the linux-stable tree. The result lead me to this commit: # first bad commit: [02b771b64b73226052d6e731a0987db3b47281e9] ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations commit 02b771b64b73226052d6e731a0987db3b47281e9 Author: Lv Zheng <lv.zh...@intel.com> Date: Wed Aug 12 11:12:02 2015 +0800 ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations It is proven that Windows evaluates _Qxx handlers in a parallel way. This patch follows this fact, splits _Qxx evaluations from the NOTIFY queue to form a separate queue, so that _Qxx evaluations can be queued up on different CPUs rather than being queued up on a CPU0 bound queue. Event handling related callbacks are also renamed and sorted in this patch. Link: https://bugzilla.kernel.org/show_bug.cgi?id=94411 Reported-and-tested-by: Gabriele Mazzotta <gabriele....@gmail.com> Signed-off-by: Lv Zheng <lv.zh...@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> The laptop was purchased from tigerdirect. Here's link to specs: http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=8556911 The laptop appears to be a re-branded Acer Aspire E1-570: http://www.acer.com/ac/en/SI/content/model/NX.MGUEX.001 Both have Insyde UEFI firmware. The latest version for both is v2.06 and have same release date, 11/11/2013, according to the Acer & Gateway support web sites, although the firmware reports an Oct date. I realize it's quite likely that the laptop's firmware is the root cause of the problem. However, since the problem did not exist on older kernels, I hope a patch or workaround can be identified that will allow me to make good use of this laptop. I assume this should also be reported to bugzilla.kernel.org. It is convenient to have the ubuntu-bug command do initial data collection. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-31-generic 4.4.0-31.50 ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13 Uname: Linux 4.4.0-31-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.1 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: buus 1830 F.... pulseaudio CurrentDesktop: Unity Date: Thu Jul 14 18:11:02 2016 HibernationDevice: RESUME=UUID=aa093ba8-768a-4c3f-a993-de6331fe2190 InstallationDate: Installed on 2016-07-01 (12 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) MachineType: Gateway NE570 ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-31-generic.efi.signed root=UUID=b3005ae3-98ce-446f-a4d9-8af24cf4c3ae ro vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-4.4.0-31-generic N/A linux-backports-modules-4.4.0-31-generic N/A linux-firmware 1.157.2 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/08/2013 dmi.bios.vendor: Insyde Corp. dmi.bios.version: V2.06 dmi.board.asset.tag: Type2 - Board Asset Tag dmi.board.name: EA50_CX dmi.board.vendor: Gateway dmi.board.version: V2.06 dmi.chassis.asset.tag: Acer Asset Tag String dmi.chassis.type: 10 dmi.chassis.vendor: Insyde Corp. dmi.chassis.version: V2.06 dmi.modalias: dmi:bvnInsydeCorp.:bvrV2.06:bd10/08/2013:svnGateway:pnNE570:pvrV2.06:rvnGateway:rnEA50_CX:rvrV2.06:cvnInsydeCorp.:ct10:cvrV2.06: dmi.product.name: NE570 dmi.product.version: V2.06 dmi.sys.vendor: Gateway
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