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Testing For The Latest Linux Kernel Power Regression

Filed under
Graphics/Benchmarks

Frame-buffer compression (FBC) support was disabled by default in the Linux 3.15 stable series for Haswell hardware and newer since the support wasn't mature and there were Intel HD Graphics users reporting issues with this feature being turned on, so it was disabled by default and hidden behind a kernel module parameter. After an Arch Linux user experienced a 4+ Watt increase in power draw for his Apple laptop, he bisected it to this FBC feature, but Intel Linux developers weren't expecting FBC to make such a huge difference in power draw. The matter is still being investigated but FBC simply can't be flipped back on by default since the code is incomplete and there's still some unmerged patches under review that won't make it until at least the Linux 3.18 kernel.

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