From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [RFC PATCH] ASoC: codec: hdac_hdmi: no checking monitor in hw_params Date: Mon, 06 May 2019 17:50:19 +0200 Message-ID: References: <1557125960-29353-1-git-send-email-libin.yang@intel.com> <5286a2bd-cb71-8094-84d5-6ac2ad2b1c02@linux.intel.com> Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 046ACF80C07 for ; Mon, 6 May 2019 17:50:19 +0200 (CEST) In-Reply-To: <5286a2bd-cb71-8094-84d5-6ac2ad2b1c02@linux.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" To: Pierre-Louis Bossart Cc: libin.yang@intel.com, alsa-devel@alsa-project.org, broonie@kernel.org, subhransu.s.prusty@intel.com, samreen.nilofer@intel.com List-Id: alsa-devel@alsa-project.org 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@intel.com wrote: > >>> From: Libin Yang > >>> > >>> 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. Takashi