Public bug reported: I have two Lenovo T410s that I upgraded from 14.04 to 16.04. Since then, one is working fine while the other shows mainly an ever disappearing screen and flickering.
I have asked here: https://askubuntu.com/questions/947233/i-upgraded-from-kubuntu-14-04-lts-to-16-04-lts-and-now-my-screen-shows-up-and-di?noredirect=1#comment1506995_947233 I also found I am not the only one: https://askubuntu.com/questions/927407/flickering-screen-with-intel-graphics-on-ubuntu-17-04?noredirect=1#comment1507937_927407 The latter has tried pretty much that could be tried already, to no avail. I think that I can help with this problem, since my two T410s are identical in hard- and software, including BIOS, except that one is a type 2924 (with NVIDIA-card, though disabled in the BIOS), and the other one is a 2904 (without NVIDIA card). I have checked for differences at boot time and found DMAR as major difference: T410s, 2924: [ 0.335616] DMAR: Disabling batched IOTLB flush on Ironlake T410s, 2904: [ 0.355681] DMAR: BIOS has allocated no shadow GTT; disabling IOMMU for graphics Should this be initially at the root of the problem, I'd consider the kernel package as responsible, therefore I marked it as above. The outputs of lspci -k | grep -EA3 'VGA|3D|Display' are identical to the point. ** Affects: linux (Ubuntu) Importance: Undecided Status: 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/1712508 Title: Disappearing screen and flickering after upgrade to 16.04 Status in linux package in Ubuntu: Incomplete Bug description: I have two Lenovo T410s that I upgraded from 14.04 to 16.04. Since then, one is working fine while the other shows mainly an ever disappearing screen and flickering. I have asked here: https://askubuntu.com/questions/947233/i-upgraded-from-kubuntu-14-04-lts-to-16-04-lts-and-now-my-screen-shows-up-and-di?noredirect=1#comment1506995_947233 I also found I am not the only one: https://askubuntu.com/questions/927407/flickering-screen-with-intel-graphics-on-ubuntu-17-04?noredirect=1#comment1507937_927407 The latter has tried pretty much that could be tried already, to no avail. I think that I can help with this problem, since my two T410s are identical in hard- and software, including BIOS, except that one is a type 2924 (with NVIDIA-card, though disabled in the BIOS), and the other one is a 2904 (without NVIDIA card). I have checked for differences at boot time and found DMAR as major difference: T410s, 2924: [ 0.335616] DMAR: Disabling batched IOTLB flush on Ironlake T410s, 2904: [ 0.355681] DMAR: BIOS has allocated no shadow GTT; disabling IOMMU for graphics Should this be initially at the root of the problem, I'd consider the kernel package as responsible, therefore I marked it as above. The outputs of lspci -k | grep -EA3 'VGA|3D|Display' are identical to the point. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1712508/+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
