On a reboot the backlight is turned on very early in the process, before the driver is loaded, probably by the bios. This is obvious because grub is able to display, so on a reboot the driver does not have to turn on the backlight, it is already on, whereas on a resume the backlight needs to be explicitly turned on by the operating system since the bios is only involved to the extent of signalling the ACPI state. However even if there is a bug in the bios with respect to supporting whatever mechanism the driver is attempting to use to manage the hardware display state, on Ubuntu 13 and earlier the display was occasionally turned on by resume, whereas now it is never turned on.
Please tell me what I have to do to resolve the "incomplete" status of this problem. -- 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/1392460 Title: resume hang ubuntu 14.10 kernel 3.16 Status in linux package in Ubuntu: Incomplete Bug description: Since upgrading to 14.10 every time I open the laptop lid the system hangs after enabling the keyboard but before turning on the display. That is the backlight on the LED screen is not turned on. This issue has occurred occasionally since 12.4, but is now completely consistent. ProblemType: Bug DistroRelease: Ubuntu 14.10 Package: linux-image-3.16.0-24-generic 3.16.0-24.32 ProcVersionSignature: Ubuntu 3.16.0-24.32-generic 3.16.4 Uname: Linux 3.16.0-24-generic x86_64 ApportVersion: 2.14.7-0ubuntu8 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: jcobban 3455 F.... pulseaudio /dev/snd/controlC0: jcobban 3455 F.... pulseaudio CurrentDesktop: Unity Date: Thu Nov 13 14:51:39 2014 HibernationDevice: RESUME=UUID=e1d460c4-e29e-470e-a302-7891166d98f7 MachineType: Dell Inc. Vostro 3555 ProcFB: 0 radeondrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-24-generic root=UUID=5850bfca-8269-4a92-8fda-798e6557b0bd ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.16.0-24-generic N/A linux-backports-modules-3.16.0-24-generic N/A linux-firmware 1.138 SourcePackage: linux UpgradeStatus: Upgraded to utopic on 2014-11-12 (1 days ago) WifiSyslog: Nov 13 14:34:15 jcobban-laptop kernel: [ 1205.903943] systemd-hostnamed[4497]: Warning: nss-myhostname is not installed. Changing the local hostname might make it unresolveable. Please install nss-myhostname! dmi.bios.date: 10/24/2011 dmi.bios.vendor: Dell Inc. dmi.bios.version: A04 dmi.board.name: 0K89MF dmi.board.vendor: Dell Inc. dmi.board.version: A04 dmi.chassis.type: 8 dmi.chassis.vendor: Dell Inc. dmi.chassis.version: Not Specified dmi.modalias: dmi:bvnDellInc.:bvrA04:bd10/24/2011:svnDellInc.:pnVostro3555:pvrNotSpecified:rvnDellInc.:rn0K89MF:rvrA04:cvnDellInc.:ct8:cvrNotSpecified: dmi.product.name: Vostro 3555 dmi.product.version: Not Specified dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1392460/+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
