Re: [PATCH v2] ALSA: hda - Fix Skylake codec timeout

[Takashi Iwai <tiwai@suse.de>]

On Thu, 16 Jul 2015 17:31:33 +0200,
David Henningsson wrote:
> 
> 
> 
> On 2015-07-16 17:14, Yang, Libin wrote:
> >> -----Original Message-----
> >> From: David Henningsson [mailto:david.henningsson@canonical.com]
> >> Sent: Thursday, July 16, 2015 4:39 PM
> >> To: tiwai@suse.de; hui.wang@canonical.com; alsa-devel@alsa-
> >> project.org; Yang, Libin; Lin, Mengdong
> >> Cc: David Henningsson
> >> Subject: [PATCH v2] ALSA: hda - Fix Skylake codec timeout
> >>
> >> When the controller is powered up but the HDMI codec is powered
> >> down
> >> on Skylake, the power well is turned off. When the codec is then
> >> powered up again, we need to poke the codec a little extra to make
> >> sure it wakes up. Otherwise we'll get sad "no response from codec"
> >> messages and broken audio.
> >
> > Thanks for finding this issue.
> >
> > Could you please give us you test case? We didn't meet such issue
> > before. I would like do a full test on it.
> 
> The test case is:
> 
>   - Install Ubuntu 15.04.
>   - Upgrade to kernel 4.1.
>   - Boot the new kernel.
> 
> Note: I believe Hui tested with 4.1 and got this error. In my case I 
> have been running a hybrid kernel: Ubuntu 15.04, kernel 3.19.0-23.24 
> (which has a backported i915 driver), and then the alsa-daily DKMS on 
> top of that.
> 
> I can email you off-list with details about the machine I tested it on, 
> if you like.

Did you hotplug the device or is it booted while plugged?
I had an unstable communication at hotplug / unplug on SKL at the last
time, too.  But the boot with the DP plugged worked well even on an
old SKL box.


Takashi