Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?
Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.16 kernel[0]. If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'. If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'. Once testing of the upstream kernel is complete, please mark this bug as "Confirmed". Thanks in advance. [0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.17-rc3 ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Changed in: linux (Ubuntu) Status: Confirmed => Incomplete -- 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/1767504 Title: Dell XPS 15 9560 - No brightness control Status in linux package in Ubuntu: Incomplete Bug description: Hello, I have the problem that I cannot control the screen brightness on my XPS 15 9560 notebook. /sys/class/backlight is empty. I'm running latest Dell BIOS firmware 1.9.4. I tried all kinds of kernel parameters, such as acpi_osi and acpi_backlight, but without any effect. I'm running with Intel graphics card in UEFI mode. kern.log attached. root@eris:/etc/default# uname -a Linux eris 4.15.0-20-generic #21-Ubuntu SMP Tue Apr 24 06:16:15 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1767504/+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
