From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pascal Wichmann Subject: Problems with the DP MST audio support patchset Date: Wed, 29 Mar 2017 12:42:31 +0200 Message-ID: <6800ee6e-31c2-b5eb-fbb2-6826d8c66dc9@pa-w.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from web02.pwsrv.de (web02.pwsrv.de [188.68.38.65]) by alsa0.perex.cz (Postfix) with ESMTP id B0DEE266EF9 for ; Wed, 29 Mar 2017 12:42:34 +0200 (CEST) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Libin Yang , alsa-devel@alsa-project.org Cc: Pascal Wichmann List-Id: alsa-devel@alsa-project.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hello, I am not sure whether alsa-devel is the right place for this kind of question. If it is not, please tell me a better place for them. I am building my kernel against the drm-tip freedesktop repository which includes the patches from December 2016 (message id <1480992519-108079-1-git-send-email-libin.yang@intel.com> and follow-ups on alsa-devel). I am using a ThinkPad X250 and the ThinkPad Ultra Dock with the HDMI output connected to my YAMAHA HTR-2866; this hdmi output is seen as display port and uses DP MST from the dock. In principle, everything is working quite well; however, I frequently recognize two weird behaviours: * First of all, my audio receiver has 5.1 support. When I configure my laptop to send 5.1 audio using alsa or pulseaudio, there is only silence and no audio signal reaches the receiver; however, when I choose 7.1 digital surround (which my receiver actually does not suppo rt natively), everything works well and the two additional speakers are split to the existing ones (I do not know whether alsa/the kernel or the receiver does this, probably it is the receiver). This problem is pretty much only esthetical, as everything works fine if I use the 7.1 "work-around" (Digital Stereo does work also, but obviously does not support the full 5.1 setup) * The other problem -- which is actually very annoying -- is that there frequently is silence though there is audio playing; this happens now and then, but when there has been *no* output for a while, it always happens a few seconds after starting the new output and lasts for two to three seconds. During these periods of silence, the icons on my receiver indicating that there is an audio source are also gone. This problem occurs with 7.1 configuration as well as with Digital Stereo. I am not sure what these problems are caused by and do not know what kin d of debug information you may require to get more hints on how to solve them. Any hints are appreciated. Thank you for your advice, Pascal Wichmann -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE/gJ8Tpn0OtJz8hxD6+YIa34W/zYFAljbj5cACgkQ6+YIa34W /zbIVg//QP4A0wUE2MyaEAenN8nUpNV5ASglRTZ0N5hXBjD+B/sxIMkJdtSynlcB eBYL90ZLuFHxdfXsltifeY29D7CaHfyqQCeJUfzV+RgUGrlv0wqk2vA9Dfc+RTIT PBORlyuknqIV14z8vxMGO/1+Po/S8AFplK/QJs9Y+irGAX+CAhBMlVMt8V5rbL+e oD8KRWgPIwuYShhd0f3tmgqdhRn9RUQgBaYOaq1pXdI/nNDHZuRA021zytkkV4rR NGG2zOsgrrXo82ac1AAeUXlNczqUCM7UXNLjpVYUQQotEMZd9d6oL5/Iq/bD7Z8i Z+bzOWymzaaThqarc11UL9ngJr6JsDNXgdDrLgLbkSE1r6Knq66qzOmzZL7qeUDI 1JeCNkmztn82VLovRogQTY8p8Ye7gXwVUPNDocCoeBKgRA6u2VGs+zJljCDOiyT9 cCA+QGMpRMz+KLt82Bt5/vE6TzngUEOZli34wNhf6DaHYo+0j4TpiCZT3roIVlp+ C+tPvDsbt9SfVLKvmoDCKAS8o5wp7+jESAsTEMzssBeN6LYKTWeAJeZHymf17ckb Y3oub8Wk5bEvZh0AO5q7wqdWMLuTc9BSmJ8eJA0jNV+m9sGKxaTB/qFMfNoJjfFD yvBBeYvic0btTtOiQAPEia1igNR9vt1hpj5wCI6xNQwSekM1bOQ= =/6Dp -----END PGP SIGNATURE-----