AMD Releases ACPI Header For Open-Source GPU Driver
Written by Michael Larabel in AMD on 28 July 2012 at 08:02 AM EDT. 42 Comments
For those that didn't notice, this week AMD released a new header that defines the AMD ACPI interface used for laptops, PowerXpress, and chipset-specific functionality.

This new header defines four ACPI control methods used by AMD graphics hardware and then related functionality to them. The four AMD ACPI methods are ATIF, ATPX, ATRM, and ATCS.

The new header can be viewed on the dri-devel mailing list. The header file is over 400 lines of new code.

While the patch integrates the new AMD ACPI header file and updates the relevant code, still on the TODO list is hooking up and handling ACPI notifications, making PowerXpress code more robust, and implementing PCI Express Gen and width switching using ACPI.

This new AMD ACPI header file came shortly after John Bridgman was mentioning in our forums that they are working to release new power management code for their open-source Radeon Linux graphics driver. "...AMD has not yet opened up all of the PM bits of the GPU (but as I said before we are working on that again since it doesn't look like community devs are going to go any further with what has already been released), so it loses in the performance-per-watt when the system is idle (an oxymoron if ever there was one)..."

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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 10,000 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 or contacted via

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