After the first firmware boot, the firmware is capable of saving/restoring its context to/from IMR (Isolated Memory Region, set aside by BIOS on startup). This capability improves the resume speed.
Due to an unexplained issue on Up2 boards, this capability is disabled on ApolloLake.
For backwards compatibility, the regular boot flow is used with older firmware. For added peace of mind, a kernel module parameter is provided to force the regular boot flow - this shouldn't be necessary since we've been testing these patches for 6+ months.
Keyon Jie (4): ASoC: SOF: add _D3_PERSISTENT flag to fw_ready message ASoC: SOF: Intel: hda-loader: add SSP helper ASoC: SOF: Intel: hda-loader: add IMR restore support ASoC: SOF: add flag to disable IMR restore to sof_debug
Pierre-Louis Bossart (1): ASoC: SOF: Intel: use inclusive language for SSP clocks
include/sound/sof/info.h | 1 + include/uapi/sound/sof/abi.h | 2 +- sound/soc/sof/intel/hda-loader.c | 68 +++++++++++++++++++++++++++----- sound/soc/sof/intel/hda.h | 6 +-- sound/soc/sof/sof-priv.h | 3 ++ 5 files changed, 66 insertions(+), 14 deletions(-)