Linux 5.0.1 Lands Fixes For AMD Zen CPB, MacBook Pro Booting Issue

Written by Michael Larabel in Linux Kernel on 10 March 2019 at 08:21 AM EDT. 5 Comments
It's been just one week since the debut of the big Linux 5.0 kernel release and today that's been succeeded by Linux 5.0.1 as the first fix-things-up release.

Greg Kroah-Hartman today released Linux 5.0.1 alongside other stable maintenance point releases. On the Linux 5.0.1 front there are some notable changes include:

- Setting the X86_FEATURE_CPB bit unconditionally for all AMD Family 17h "Zen" processors. Some 17h models do not have the CPB set even though all the 17h CPUs support it, so now the kernel is unconditionally setting the bit... CPB is the Core Performance Boost mode. Two years ago there were problems with CPB not getting set so it was selectively being enabled, but now that work from two years ago is being expanded to unconditionally enable it for all Zen CPUs. See that aforelinked article for some benchmarks on the impact when CPB is disabled vs. enabled.

- Fixes for potential Spectre V1 vulnerabilities within the Applicom driver.

- A fix allowing for the USB role feature to work on the Intel Kabylake NUC hardware.

- The recently talked about fix that was added to Linux 5.1 and now back-ported for addressing a fix from some MacBook Pros from booting.

- Various fixes to the read-only "EROFS" file-system driver.

- Various other fixes.

In total several hundred lines worth of code changes as outlined with all of the changes in the 5.0.1 announcement.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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