On Mon, 06 May 2019 17:37:32 +0200, Pierre-Louis Bossart wrote: > > On 5/6/19 1:59 AM, libin.yang@xxxxxxxxx wrote: > > From: Libin Yang <libin.yang@xxxxxxxxx> > > > > This patch move the check of monitor from hw_params to trigger callback. > > > > The original code will check the monitor presence in hw_params. If the > > monitor doesn't exist, hw_params will return -ENODEV. Mostly this is OK. > > > > However, pulseaudio will check the pcm devices when kernel is booting up. > > It will try to open, set hw_params, prepare such pcm devices. We can't > > guarantee that the monitor will be connected when kernel is booting up. > > Especially, hdac_hdmi will export 3 pcms at most. It's hard to say users > > will connect 3 monitors to the HDMI/DP ports. This will cause pulseaudio > > fail in parsing the pcm devices because the driver will return -ENODEV in > > hw_params. > > > > This patch tries to move the check of monitor presence into trigger > > callback. This can "trick" the pulseaudio the pcm is ready. > > > > This bug is found when we try to enable HDMI detection in > > gnome-sound-setting for ASoC hdac_hdmi. After we enable the hdmi in UCM, > > pulseaudio will try to parse the hdmi pcm devices. It will cause failure if > > there are no monitors connected. > > Out of curiosity, how is this handled in the legacy driver? I haven't > done this for a long time but I remember very clearly being able to > play on the HDMI:3,7, etc devices without any monitors > connected. You'd get of course no sound but there was no error > reported to userspace. The hardware is perfectly capable of pushing > samples into the display controller using the HDAudio/iDisp link. As mentioned in the thread, PA just picks up the stream that is connected via a monitor by checking / notified by the corresponding Jack control. On hdac_hdmi driver, the jack control has different base name that is irrelevant with the output pins, so PA doesn't know how to interpret it, hence it's ignored. thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
