I could reproduce with kernel 3.11.0.3.4 and bios A09. Is there any difference between this kernel and the one provided in your link ?
The bug doesn't seems to happens if I don't set "acpi_osi=Linux acpi_backlight=vendor" in my /etc/default/grub. But I wouldn't be able to modify lightness then. sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date output is: A09 06/25/2013 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1214287 Title: [Dell Inspiron 15R 5521] suspend/resume failure To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1214287/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
