Many Intel Bay Trail Devices Have Been Borked On Linux For The Past Year
While my Bay Trail Linux experiences had been positive, a Phoronix reader wrote in this morning to tell me about some widespread Bay Trail Linux kernel troubles that have been happening for the past year and also impact Braswell. Kernels newer than Linux 3.16 are able to cause random X session freezes. This issue has occurred on many different notebooks, tablets, desktops, and other Bay Trail devices. The particular user that wrote in reportedly has 16 systems affected by this issue.
This FreeDesktop.org bug report was initially opened in January of 2015 about "full system freezes" and the original poster bisected it down to a bad commit within the i915 ValleyView code. There was more than 100 comments to this bug report without much action by Intel's Linux graphics developers when finally in December they realized it might not be a bug in the Intel i915 DRM driver but rather a behavior change in the GPU driver that made a CPU cstates issue more pressing. The known workaround that came up in the year of bug reports is that booting a modern Linux kernel with intel_idle.max_cstate=1 will fix the system freezes. However, using that option will also cause your system's power use to go up due to reduced power efficiency of the CPU.
In December when shifting the blame to the other part of the kernel, this Kernel.org bug report was opened and in the few months since has received more than 120 comments of the same issue occurring on many different Bay Trail systems.
As of right now and even with the many complaints about this bug on a multitude of systems and Linux 4.5 set to be released this weekend, this bug hasn't been properly resolved yet.