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New Intel DRM Code For Linux 3.17 Works On PSR, SOix Sleep State
Intel had already been working on Linux 3.17 graphics driver improvements since the beginning of the month and today Daniel Vetter of Intel OTC has announced another round of improvements now found in their DRM Git repository for testing:
- Accurate front-buffer tracking and front-buffer rendering invalidate, plus flush and flip events. These internal changes are working towards PSR support. PSR is short for Panel Self Refresh and is a feature found as part of DisplayPort 1.3 and eDP 1.3. Panel Self Refresh allows for conserving power use by being able to power down the GPU and related circuitry when displaying a static image. PSR is just about not continuously refreshing the display when the system is idle and screen contents aren't changing. This code indirectly also helps out work towards frame-buffer compression.
- Related to the aforementioned work are also Panel Self Refresh updates specific to Intel's forthcoming Broadwell hardware.
- Run-time suspend hardware work to support the new SOix sleep state. SOix sleep state was added with Intel Haswell CPUs as an "Active Idle" state that is an extremely low-power state.
- Universal plane support for cursors.
- Bay Trail write-enable PTS bit support.
- MMIO-based flips in place of blitter-ring-based flipping.
- Interrupt handling race fixes.
- Various other fixes and enhancements.
Expect more work still to come about with at least another month to go until the Linux 3.17 kernel merge window is to open. Those wishing to test out this latest Intel DRM graphics driver code can find the Git details via this mailing list message.