Hi Mark and Pierre, here's a patch series to address an issue that popped up after SOF changed from hdac-hdmi to snd-hda-codec-hdmi:
"failed to get afg sub nodes on ChromeOS devices" https://github.com/thesofproject/linux/issues/1642
v2 changes: - rebased on top of broonie/for-next - added Takashi's reviewed-by to the one HDA patch, agreed the series should go via asoc tree
This is fairly hard to hit and only occurs on some devices (most current reports are Gemini Lake based Chromebooks), but when it does, it is rather severe as the whole SOF probe fails because of this, and user is left without sound.
First fix is to optimize out one power down/up cycle from the probe process. On platforms such as GLK, each time audio driver does acomp's get_power(), graphics typically needs to do a modeset due to clocking requirements for the HDA bus. This can cause display to flash when audio is probed, plus in the reported cases on GLK, can lead to probe failures.
The above change doesn't cover all reported cases, so additionally retry logic is added to snd_hda_get_sub_nodes() calls on Intel platforms. Multiple other approaches were investigated, but a simple retry -- although less than ideal -- in the end proved to be most reliable solution. HDA dump on one affected Acer Chromebook looks like this:
# codec initialization goes as normal with multiple successful cmds udevd-9486 [001] .... 3910.087791: hda_send_cmd: [0000:00:0e.0:2] val=0x207f1c00 udevd-9486 [001] .... 3910.087857: hda_get_response: [0000:00:0e.0:2] val=0x18560010 udevd-9486 [001] .... 3910.087858: hda_send_cmd: [0000:00:0e.0:2] val=0x207f0700 udevd-9486 [001] .... 3910.087931: hda_get_response: [0000:00:0e.0:2] val=0x00000000 udevd-9486 [001] .... 3910.087932: hda_send_cmd: [0000:00:0e.0:2] val=0x20bf8100 udevd-9486 [001] .... 3910.088040: hda_get_response: [0000:00:0e.0:2] val=0x00000001 udevd-9486 [001] .... 3910.088044: hda_send_cmd: [0000:00:0e.0:2] val=0x20b78103 # here get params for AC_PAR_NODE_COUNT fails, 0xffffffff is returned udevd-9486 [001] .... 3910.088048: hda_send_cmd: [0000:00:0e.0:2] val=0x201f0004 udevd-9486 [001] .... 3911.090131: hda_get_response: [0000:00:0e.0:2] val=0xffffffff # retry is successful udevd-9486 [001] .... 3911.090152: hda_send_cmd: [0000:00:0e.0:2] val=0x201f0004 udevd-9486 [001] .... 3911.090288: hda_get_response: [0000:00:0e.0:2] val=0x00020006
Kai Vehmanen (3): ASoC: SOF: Intel: refactor i915_get/put functions ASoC: SOF: Intel: do not disable i915 power during probe ALSA: hda/hdmi - add retry logic to parse_intel_hdmi()
sound/pci/hda/patch_hdmi.c | 7 +++++-- sound/soc/sof/intel/hda-codec.c | 21 ++++++--------------- sound/soc/sof/intel/hda.c | 3 ++- sound/soc/sof/intel/hda.h | 7 +++---- 4 files changed, 16 insertions(+), 22 deletions(-)