And can you ensure 4.4 final is bad? It is available from: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4-wily/
If 4.4 final is bad, I can reverse bisect between 4.4 and 4.5-rc1. However, if 4.4 final is good(Which it probably will be), we will have to go back to performing a standard bisect between upstream 4.4.40 and 4.4.41. The regression came via a 4.4.41 stable update from mainline. However, the bug is not happening in any of the other 4.5-rc1 or greater kernels that you tested. It might take a lot of testing from the results posted in comment #31 to find the commit that fixes the bug. It might be the regression was introduced in one of the 4.5, 4.7 or 4.9 release candidates and fixed right away. Although it should have came down in newer 4.4 stable updates but 4.4.55 still has the bug also per comment #31. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1667323 Title: Backlight control does not work and there are no entries in /sys/class/backlight Status in linux package in Ubuntu: Triaged Status in linux source package in Xenial: Triaged Bug description: It was working fine until today. The folder /sys/class/backlight/ use to have "acpi_video0/brightness", but now is empty. I am using Nvidia Proprietary driver 340.101 (proprietary, tested). The problem persists even with the 304 driver. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-64-generic 4.4.0-64.85 ProcVersionSignature: Ubuntu 4.4.0-64.85-generic 4.4.44 Uname: Linux 4.4.0-64-generic x86_64 NonfreeKernelModules: nvidia_uvm nvidia ApportVersion: 2.20.1-0ubuntu2.5 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: desgua 2028 F.... pulseaudio /dev/snd/controlC0: desgua 2028 F.... pulseaudio CurrentDesktop: Unity Date: Thu Feb 23 11:31:18 2017 HibernationDevice: RESUME=UUID=f23a6347-9483-460e-aa29-cbc47850f890 InstallationDate: Installed on 2014-05-01 (1028 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417) Lsusb: Bus 002 Device 003: ID 064e:a127 Suyin Corp. Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: Hewlett-Packard HP Pavilion dv6 Notebook PC ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-64-generic root=/dev/mapper/ubuntu--vg-root ro RelatedPackageVersions: linux-restricted-modules-4.4.0-64-generic N/A linux-backports-modules-4.4.0-64-generic N/A linux-firmware 1.157.8 SourcePackage: linux UpgradeStatus: Upgraded to xenial on 2016-08-17 (189 days ago) dmi.bios.date: 12/03/2009 dmi.bios.vendor: Hewlett-Packard dmi.bios.version: F.13 dmi.board.asset.tag: Base Board Asset Tag dmi.board.name: 3659 dmi.board.vendor: Hewlett-Packard dmi.board.version: 32.23 dmi.chassis.type: 10 dmi.chassis.vendor: Hewlett-Packard dmi.chassis.version: N/A dmi.modalias: dmi:bvnHewlett-Packard:bvrF.13:bd12/03/2009:svnHewlett-Packard:pnHPPaviliondv6NotebookPC:pvr049D210000241210000020000:rvnHewlett-Packard:rn3659:rvr32.23:cvnHewlett-Packard:ct10:cvrN/A: dmi.product.name: HP Pavilion dv6 Notebook PC dmi.product.version: 049D210000241210000020000 dmi.sys.vendor: Hewlett-Packard To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1667323/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
