From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre-Louis Bossart Subject: Re: [RFC PATCH] ASoC: codec: hdac_hdmi: no checking monitor in hw_params Date: Mon, 6 May 2019 10:47:25 -0500 Message-ID: <5286a2bd-cb71-8094-84d5-6ac2ad2b1c02@linux.intel.com> References: <1557125960-29353-1-git-send-email-libin.yang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id E70C3F80C07 for ; Mon, 6 May 2019 17:47:29 +0200 (CEST) In-Reply-To: Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" To: Takashi Iwai 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 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?