The upcoming Linux 6.19 kernel cycle is set to introduce initial support for Xe3P graphics to be found initially with Nova Lake processors. While that initial support is landing for Linux 6.19, other extra Xe3P features are still to be added to the open-source kernel driver over coming release cycles. One of those extra features being currently tackled is a new element with Xe3P_LPD: the ability to use the system cache for FBC.
Xe3P_LPD will allow reserving an area of the system cache for use with frame-buffer compression (FBC). For “xe3p_lpd onwards”, FBC can leverage the system cache for better efficiency:
“As FBC can utilze the system cache in xe3p_lpd onwards, we need a way to track which fbc instance is utilizing this cache…”
The goal is to reduce memory system power consumption while idle for better power efficiency with this new feature.
“One of the FBC instances can utilize the reserved area of SoC level cache for the fbc transactions to benefit reduced memory system power especially in idle scenarios. Reserved area of the system cache can be assigned to an fbc instance by configuring the cacheability configuration register with offset of the compressed frame buffer in stolen memory of that fbc. There is a limit to this reserved area which is programmable and for xe3p_lpd the limit is defined as 2MB.”
This patch series is under review for wiring up this system cache for FBC to the open-source Intel kernel graphics driver. It’s too late for Linux 6.19 but given the timing this feature will presumably be ready by the follow-on Linux v7.0 cycle.
