Hi Pierre, >-----Original Message----- >From: Pierre-Louis Bossart [mailto:pierre-louis.bossart@xxxxxxxxxxxxxxx] >Sent: Monday, May 6, 2019 11:54 PM >To: Takashi Iwai <tiwai@xxxxxxx> >Cc: Yang, Libin <libin.yang@xxxxxxxxx>; alsa-devel@xxxxxxxxxxxxxxxx; >broonie@xxxxxxxxxx; subhransu.s.prusty@xxxxxxxxx; >samreen.nilofer@xxxxxxxxx >Subject: Re: [RFC PATCH] ASoC: codec: hdac_hdmi: no checking >monitor in hw_params > >On 5/6/19 10:50 AM, Takashi Iwai wrote: >> On Mon, 06 May 2019 17:47:25 +0200, >> Pierre-Louis Bossart wrote: >>> >>> On 5/6/19 10:41 AM, Takashi Iwai wrote: >>>> 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. >>> >>> Yes, but do we have any error checks in the hw_params or trigger >>> cases with the legacy driver? >> >> No, it just continues playing without the actual output. > >ok, so could we remove all these error checks then for hdac_hdmi? The >problem is really the output selection on jack detect/monitor reconfigurations, >those checks don't add much value, do they? Yes, I'm planning to remove the checks in hdac_hdmi. Before that, I will do some tests on it. The monitor check in hw_params only impacts on the playback flow. Regards, Libin _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
