Re: [PATCH 1/2] ALSA: hda/hdmi: fix failures at PCM open on Intel ICL and later

From: Takashi Iwai <tiwai@suse.de>
To: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
	alsa-devel@alsa-project.org, libin.yang@linux.intel.com,
	Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Subject: Re: [PATCH 1/2] ALSA: hda/hdmi: fix failures at PCM open on Intel ICL and later
Date: Tue, 07 Jul 2020 10:13:29 +0200	[thread overview]
Message-ID: <s5h5zazg2ty.wl-tiwai@suse.de> (raw)
In-Reply-To: <20200703153818.2808592-1-kai.vehmanen@linux.intel.com>

On Fri, 03 Jul 2020 17:38:17 +0200,
Kai Vehmanen wrote:
> 
> When HDMI PCM devices are opened in a specific order, with at least one
> HDMI/DP receiver connected, ALSA PCM open fails to -EBUSY on the
> connected monitor, on recent Intel platforms (ICL/JSL and newer). While
> this is not a typical sequence, at least Pulseaudio does this every time
> when it is started, to discover the available PCMs.
> 
> The rootcause is an invalid assumption in hdmi_add_pin(), where the
> total number of converters is assumed to be known at the time the
> function is called. On older Intel platforms this held true, but after
> ICL/JSL, the order how pins and converters are in the subnode list as
> returned by snd_hda_get_sub_nodes(), was changed. As a result,
> information for some converters was not stored to per_pin->mux_nids.
> And this means some pins cannot be connected to all converters, and
> application instead gets -EBUSY instead at open.
> 
> The assumption that converters are always before pins in the subnode
> list, is not really a valid one. Fix the problem in hdmi_parse_codec()
> by introducing separate loops for discovering converters and pins.
> 
> BugLink: https://github.com/thesofproject/linux/issues/1978
> BugLink: https://github.com/thesofproject/linux/issues/2216
> BugLink: https://github.com/thesofproject/linux/issues/2217
> Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Thanks, applied.

Takashi