Another possibility is that LCD panel dithering (controlled by the i915 kernel driver) has changed between kernel versions.
If your LCD panel is natively 6-bits per channel then the kernel should be turning on dithering for you, since the shell is typically rendered as 8-bits per channel. If dithering is not enabled then you will see banding and effectively see a loss of 75% of your colours and gradients. But the tricky part is for a developer to find a machine with the same problem. The problem will be specific to your GPU model (the dithering logic in i915 varies between generations), and specific to the LCD panel type in that laptop. Effectively we will need to find a similar Haswell laptop with a similar LCD type, which is the hard part... ** Summary changed: - Colour banding and artefacts appear system-wide on an Intel HD Graphics 4400 system + Colour banding and artefacts appear system-wide on an Asus Zenbook UX303 with Intel HD 4400 graphics -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1749420 Title: Colour banding and artefacts appear system-wide on an Asus Zenbook UX303 with Intel HD 4400 graphics To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1749420/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
