[alsa-devel] [PATCH] ALSA: hda - Force polling mode on CFL for fixing codec communication

[Ughreja, Rakesh A]

>-----Original Message-----
>From: alsa-devel-bounces at alsa-project.org [mailto:alsa-devel-bounces at alsa-
>project.org] On Behalf Of Takashi Iwai
>Sent: Wednesday, March 21, 2018 2:45 PM
>To: alsa-devel at alsa-project.org
>Cc: Hui Wang <hui.wang at canonical.com>
>Subject: [alsa-devel] [PATCH] ALSA: hda - Force polling mode on CFL for fixing
>codec communication
>
>We've observed too long probe time with Coffee Lake machines, and the
>likely cause is some communication problem between the HD-audio
>controller and the codec chips.  While the controller expects an IRQ
>wakeup for each codec response, it seems sometimes missing, and it
>takes one second for the controller driver to time out and read the
>response in the polling mode.
>

I think I faced similar problem while doing the HDA ASoC work.

I don't have any way to reproduce and test this. Can we increase
the delay after the link is powered ON. The present delay is 100usec,
can we make it 521 uSec ? Possibly the codec is not ready after
the link is powered on and so it's not responding.

File: hda_intel.c

	/* 4. turn link up: set SPA to 1 and wait CPA to 1 */
	intel_ml_lctl_set_power(chip, 1);
	udelay(100); --> change this to 521.

Regards,
Rakesh