[PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[libin.yang]

From: Libin Yang <libin.yang@intel.com>

Audio stream is not continuous if using position buffer on Broadwell
HDMI audio. Sound is clipped.
Fix this issue by using POS_FIX_LPIB.

Signed-off-by: Libin Yang <libin.yang@intel.com>
---
 sound/pci/hda/hda_intel.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index b540ad7..9cd40c6 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -993,6 +993,7 @@ static struct snd_pci_quirk position_fix_list[] = {
 	SND_PCI_QUIRK(0x1565, 0x8218, "Biostar Microtech", POS_FIX_LPIB),
 	SND_PCI_QUIRK(0x1849, 0x0888, "775Dual-VSTA", POS_FIX_LPIB),
 	SND_PCI_QUIRK(0x8086, 0x2503, "DG965OT AAD63733-203", POS_FIX_LPIB),
+	SND_PCI_QUIRK(0x8086, 0x2010, "Broadwell HDMI audio", POS_FIX_LPIB),
 	{}
 };
 
-- 
1.8.3.2

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Thu,  8 May 2014 02:03:24 +0800,
libin.yang@intel.com wrote:
> 
> From: Libin Yang <libin.yang@intel.com>
> 
> Audio stream is not continuous if using position buffer on Broadwell
> HDMI audio. Sound is clipped.
> Fix this issue by using POS_FIX_LPIB.

That's odd.  The recent Intel hardware has a wallclock support, so the
position should be corrected by that.

In which situation did the problem happen?  Did it happen with every
application and any period/buffer setup?


Takashi

> 
> Signed-off-by: Libin Yang <libin.yang@intel.com>
> ---
>  sound/pci/hda/hda_intel.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> index b540ad7..9cd40c6 100644
> --- a/sound/pci/hda/hda_intel.c
> +++ b/sound/pci/hda/hda_intel.c
> @@ -993,6 +993,7 @@ static struct snd_pci_quirk position_fix_list[] = {
>  	SND_PCI_QUIRK(0x1565, 0x8218, "Biostar Microtech", POS_FIX_LPIB),
>  	SND_PCI_QUIRK(0x1849, 0x0888, "775Dual-VSTA", POS_FIX_LPIB),
>  	SND_PCI_QUIRK(0x8086, 0x2503, "DG965OT AAD63733-203", POS_FIX_LPIB),
> +	SND_PCI_QUIRK(0x8086, 0x2010, "Broadwell HDMI audio", POS_FIX_LPIB),
>  	{}
>  };
>  
> -- 
> 1.8.3.2
> 

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Yang, Libin]

Hi Takashi,

I checked the wallclock counter. The counter is OK. But it failed to correct the position.

This issue happens when we play sound on HDMI audio. We have tried with aplay and paplay. 

I have tried the buffer size of 16384, 8192 and 4096 and with the sample rate of 48KHz and 44.1KHz.

Regards,
Libin

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Thursday, May 8, 2014 1:09 PM
> To: Yang, Libin
> Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI
> Audio
> 
> At Thu,  8 May 2014 02:03:24 +0800,
> libin.yang@intel.com wrote:
> >
> > From: Libin Yang <libin.yang@intel.com>
> >
> > Audio stream is not continuous if using position buffer on Broadwell
> > HDMI audio. Sound is clipped.
> > Fix this issue by using POS_FIX_LPIB.
> 
> That's odd.  The recent Intel hardware has a wallclock support, so the
> position should be corrected by that.
> 
> In which situation did the problem happen?  Did it happen with every
> application and any period/buffer setup?
> 
> 
> Takashi
> 
> >
> > Signed-off-by: Libin Yang <libin.yang@intel.com>
> > ---
> >  sound/pci/hda/hda_intel.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> > index b540ad7..9cd40c6 100644
> > --- a/sound/pci/hda/hda_intel.c
> > +++ b/sound/pci/hda/hda_intel.c
> > @@ -993,6 +993,7 @@ static struct snd_pci_quirk position_fix_list[] = {
> >  	SND_PCI_QUIRK(0x1565, 0x8218, "Biostar Microtech", POS_FIX_LPIB),
> >  	SND_PCI_QUIRK(0x1849, 0x0888, "775Dual-VSTA", POS_FIX_LPIB),
> >  	SND_PCI_QUIRK(0x8086, 0x2503, "DG965OT AAD63733-203",
> POS_FIX_LPIB),
> > +	SND_PCI_QUIRK(0x8086, 0x2010, "Broadwell HDMI audio",
> POS_FIX_LPIB),
> >  	{}
> >  };
> >
> > --
> > 1.8.3.2
> >

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Thu, 8 May 2014 05:48:04 +0000,
Yang, Libin wrote:
> 
> Hi Takashi,
> 
> I checked the wallclock counter. The counter is OK. But it failed to correct the position.

So, how wrong the position buffer is?  Is the problem intermittent?
Please elaborate more.


Takashi

> This issue happens when we play sound on HDMI audio. We have tried with aplay and paplay. 
> 
> I have tried the buffer size of 16384, 8192 and 4096 and with the sample rate of 48KHz and 44.1KHz.
> 
> Regards,
> Libin
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de]
> > Sent: Thursday, May 8, 2014 1:09 PM
> > To: Yang, Libin
> > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI
> > Audio
> > 
> > At Thu,  8 May 2014 02:03:24 +0800,
> > libin.yang@intel.com wrote:
> > >
> > > From: Libin Yang <libin.yang@intel.com>
> > >
> > > Audio stream is not continuous if using position buffer on Broadwell
> > > HDMI audio. Sound is clipped.
> > > Fix this issue by using POS_FIX_LPIB.
> > 
> > That's odd.  The recent Intel hardware has a wallclock support, so the
> > position should be corrected by that.
> > 
> > In which situation did the problem happen?  Did it happen with every
> > application and any period/buffer setup?
> > 
> > 
> > Takashi
> > 
> > >
> > > Signed-off-by: Libin Yang <libin.yang@intel.com>
> > > ---
> > >  sound/pci/hda/hda_intel.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> > > index b540ad7..9cd40c6 100644
> > > --- a/sound/pci/hda/hda_intel.c
> > > +++ b/sound/pci/hda/hda_intel.c
> > > @@ -993,6 +993,7 @@ static struct snd_pci_quirk position_fix_list[] = {
> > >  	SND_PCI_QUIRK(0x1565, 0x8218, "Biostar Microtech", POS_FIX_LPIB),
> > >  	SND_PCI_QUIRK(0x1849, 0x0888, "775Dual-VSTA", POS_FIX_LPIB),
> > >  	SND_PCI_QUIRK(0x8086, 0x2503, "DG965OT AAD63733-203",
> > POS_FIX_LPIB),
> > > +	SND_PCI_QUIRK(0x8086, 0x2010, "Broadwell HDMI audio",
> > POS_FIX_LPIB),
> > >  	{}
> > >  };
> > >
> > > --
> > > 1.8.3.2
> > >
> 

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Yang, Libin]

Hi Takashi,

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Thursday, May 8, 2014 1:51 PM
> To: Yang, Libin
> Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI
> Audio
> 
> At Thu, 8 May 2014 05:48:04 +0000,
> Yang, Libin wrote:
> >
> > Hi Takashi,
> >
> > I checked the wallclock counter. The counter is OK. But it failed to correct
> the position.
> 
> So, how wrong the position buffer is?  Is the problem intermittent?
> Please elaborate more.

The issue is the position is almost always inaccurate. You will hear there is intermittent noise in the sound. And the sound is played faster than it should be.

The following message is what I got from dmesg:

[ 73.278117] snd_hda_intel 0000:00:03.0: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj.
[ 73.528575] snd_hda_intel 0000:00:03.0: Unstable LPIB (26240 >= 24064); disabling LPIB delay counting

Do you think the print of wallclk and position information in the function azx_position_ok() is useful to you? If yes, I will add debug code to print the info.

> 
> 
> Takashi
> 
> > This issue happens when we play sound on HDMI audio. We have tried
> with aplay and paplay.
> >
> > I have tried the buffer size of 16384, 8192 and 4096 and with the sample
> rate of 48KHz and 44.1KHz.
> >
> > Regards,
> > Libin
> >
> > > -----Original Message-----
> > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > Sent: Thursday, May 8, 2014 1:09 PM
> > > To: Yang, Libin
> > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > HDMI Audio
> > >
> > > At Thu,  8 May 2014 02:03:24 +0800,
> > > libin.yang@intel.com wrote:
> > > >
> > > > From: Libin Yang <libin.yang@intel.com>
> > > >
> > > > Audio stream is not continuous if using position buffer on
> > > > Broadwell HDMI audio. Sound is clipped.
> > > > Fix this issue by using POS_FIX_LPIB.
> > >
> > > That's odd.  The recent Intel hardware has a wallclock support, so
> > > the position should be corrected by that.
> > >
> > > In which situation did the problem happen?  Did it happen with every
> > > application and any period/buffer setup?
> > >
> > >
> > > Takashi
> > >
> > > >
> > > > Signed-off-by: Libin Yang <libin.yang@intel.com>
> > > > ---
> > > >  sound/pci/hda/hda_intel.c | 1 +
> > > >  1 file changed, 1 insertion(+)
> > > >
> > > > diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> > > > index b540ad7..9cd40c6 100644
> > > > --- a/sound/pci/hda/hda_intel.c
> > > > +++ b/sound/pci/hda/hda_intel.c
> > > > @@ -993,6 +993,7 @@ static struct snd_pci_quirk position_fix_list[] = {
> > > >  	SND_PCI_QUIRK(0x1565, 0x8218, "Biostar Microtech", POS_FIX_LPIB),
> > > >  	SND_PCI_QUIRK(0x1849, 0x0888, "775Dual-VSTA", POS_FIX_LPIB),
> > > >  	SND_PCI_QUIRK(0x8086, 0x2503, "DG965OT AAD63733-203",
> > > POS_FIX_LPIB),
> > > > +	SND_PCI_QUIRK(0x8086, 0x2010, "Broadwell HDMI audio",
> > > POS_FIX_LPIB),
> > > >  	{}
> > > >  };
> > > >
> > > > --
> > > > 1.8.3.2
> > > >
> >


Regards,
Libin

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Thu, 8 May 2014 06:13:31 +0000,
Yang, Libin wrote:
> 
> Hi Takashi,
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de]
> > Sent: Thursday, May 8, 2014 1:51 PM
> > To: Yang, Libin
> > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI
> > Audio
> > 
> > At Thu, 8 May 2014 05:48:04 +0000,
> > Yang, Libin wrote:
> > >
> > > Hi Takashi,
> > >
> > > I checked the wallclock counter. The counter is OK. But it failed to correct
> > the position.
> > 
> > So, how wrong the position buffer is?  Is the problem intermittent?
> > Please elaborate more.
> 
> The issue is the position is almost always inaccurate. You will hear there is intermittent noise in the sound. And the sound is played faster than it should be.
> 
> The following message is what I got from dmesg:
> 
> [ 73.278117] snd_hda_intel 0000:00:03.0: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj.
> [ 73.528575] snd_hda_intel 0000:00:03.0: Unstable LPIB (26240 >= 24064); disabling LPIB delay counting
> 
> Do you think the print of wallclk and position information in the function azx_position_ok() is useful to you? If yes, I will add debug code to print the info.

It'd better to have the raw values of posbuf, lpib and wallclock for
further analysis, yes.

BTW, did you try non-snoop mode via snoop=0 option?


Takashi


> 
> > 
> > 
> > Takashi
> > 
> > > This issue happens when we play sound on HDMI audio. We have tried
> > with aplay and paplay.
> > >
> > > I have tried the buffer size of 16384, 8192 and 4096 and with the sample
> > rate of 48KHz and 44.1KHz.
> > >
> > > Regards,
> > > Libin
> > >
> > > > -----Original Message-----
> > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > Sent: Thursday, May 8, 2014 1:09 PM
> > > > To: Yang, Libin
> > > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > > HDMI Audio
> > > >
> > > > At Thu,  8 May 2014 02:03:24 +0800,
> > > > libin.yang@intel.com wrote:
> > > > >
> > > > > From: Libin Yang <libin.yang@intel.com>
> > > > >
> > > > > Audio stream is not continuous if using position buffer on
> > > > > Broadwell HDMI audio. Sound is clipped.
> > > > > Fix this issue by using POS_FIX_LPIB.
> > > >
> > > > That's odd.  The recent Intel hardware has a wallclock support, so
> > > > the position should be corrected by that.
> > > >
> > > > In which situation did the problem happen?  Did it happen with every
> > > > application and any period/buffer setup?
> > > >
> > > >
> > > > Takashi
> > > >
> > > > >
> > > > > Signed-off-by: Libin Yang <libin.yang@intel.com>
> > > > > ---
> > > > >  sound/pci/hda/hda_intel.c | 1 +
> > > > >  1 file changed, 1 insertion(+)
> > > > >
> > > > > diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> > > > > index b540ad7..9cd40c6 100644
> > > > > --- a/sound/pci/hda/hda_intel.c
> > > > > +++ b/sound/pci/hda/hda_intel.c
> > > > > @@ -993,6 +993,7 @@ static struct snd_pci_quirk position_fix_list[] = {
> > > > >  	SND_PCI_QUIRK(0x1565, 0x8218, "Biostar Microtech", POS_FIX_LPIB),
> > > > >  	SND_PCI_QUIRK(0x1849, 0x0888, "775Dual-VSTA", POS_FIX_LPIB),
> > > > >  	SND_PCI_QUIRK(0x8086, 0x2503, "DG965OT AAD63733-203",
> > > > POS_FIX_LPIB),
> > > > > +	SND_PCI_QUIRK(0x8086, 0x2010, "Broadwell HDMI audio",
> > > > POS_FIX_LPIB),
> > > > >  	{}
> > > > >  };
> > > > >
> > > > > --
> > > > > 1.8.3.2
> > > > >
> > >
> 
> 
> Regards,
> Libin
> 

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Yang, Libin]

Hi Takashi,

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Thursday, May 8, 2014 2:20 PM
> To: Yang, Libin
> Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI
> Audio
> 
> At Thu, 8 May 2014 06:13:31 +0000,
> Yang, Libin wrote:
> >
> > Hi Takashi,
> >
> > > -----Original Message-----
> > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > Sent: Thursday, May 8, 2014 1:51 PM
> > > To: Yang, Libin
> > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > HDMI Audio
> > >
> > > At Thu, 8 May 2014 05:48:04 +0000,
> > > Yang, Libin wrote:
> > > >
> > > > Hi Takashi,
> > > >
> > > > I checked the wallclock counter. The counter is OK. But it failed
> > > > to correct
> > > the position.
> > >
> > > So, how wrong the position buffer is?  Is the problem intermittent?
> > > Please elaborate more.
> >
> > The issue is the position is almost always inaccurate. You will hear there is
> intermittent noise in the sound. And the sound is played faster than it should
> be.
> >
> > The following message is what I got from dmesg:
> >
> > [ 73.278117] snd_hda_intel 0000:00:03.0: IRQ timing workaround is
> activated for card #0. Suggest a bigger bdl_pos_adj.
> > [ 73.528575] snd_hda_intel 0000:00:03.0: Unstable LPIB (26240 >=
> > 24064); disabling LPIB delay counting
> >
> > Do you think the print of wallclk and position information in the function
> azx_position_ok() is useful to you? If yes, I will add debug code to print the
> info.
> 
> It'd better to have the raw values of posbuf, lpib and wallclock for further
> analysis, yes.
> 
> BTW, did you try non-snoop mode via snoop=0 option?

I haven't tried non-snoop. Do I use `modprobe snd-hda-intel snoop=0` to use non-snoop mode?
> 
> 
> Takashi
> 
> 
> >
> > >
> > >
> > > Takashi
> > >
> > > > This issue happens when we play sound on HDMI audio. We have tried
> > > with aplay and paplay.
> > > >
> > > > I have tried the buffer size of 16384, 8192 and 4096 and with the
> > > > sample
> > > rate of 48KHz and 44.1KHz.
> > > >
> > > > Regards,
> > > > Libin
> > > >
> > > > > -----Original Message-----
> > > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > > Sent: Thursday, May 8, 2014 1:09 PM
> > > > > To: Yang, Libin
> > > > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis
> > > > > Bossart
> > > > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > > > HDMI Audio
> > > > >
> > > > > At Thu,  8 May 2014 02:03:24 +0800, libin.yang@intel.com wrote:
> > > > > >
> > > > > > From: Libin Yang <libin.yang@intel.com>
> > > > > >
> > > > > > Audio stream is not continuous if using position buffer on
> > > > > > Broadwell HDMI audio. Sound is clipped.
> > > > > > Fix this issue by using POS_FIX_LPIB.
> > > > >
> > > > > That's odd.  The recent Intel hardware has a wallclock support,
> > > > > so the position should be corrected by that.
> > > > >
> > > > > In which situation did the problem happen?  Did it happen with
> > > > > every application and any period/buffer setup?
> > > > >
> > > > >
> > > > > Takashi
> > > > >
> > > > > >
> > > > > > Signed-off-by: Libin Yang <libin.yang@intel.com>
> > > > > > ---
> > > > > >  sound/pci/hda/hda_intel.c | 1 +
> > > > > >  1 file changed, 1 insertion(+)
> > > > > >
> > > > > > diff --git a/sound/pci/hda/hda_intel.c
> > > > > > b/sound/pci/hda/hda_intel.c index b540ad7..9cd40c6 100644
> > > > > > --- a/sound/pci/hda/hda_intel.c
> > > > > > +++ b/sound/pci/hda/hda_intel.c
> > > > > > @@ -993,6 +993,7 @@ static struct snd_pci_quirk position_fix_list[]
> = {
> > > > > >  	SND_PCI_QUIRK(0x1565, 0x8218, "Biostar Microtech",
> POS_FIX_LPIB),
> > > > > >  	SND_PCI_QUIRK(0x1849, 0x0888, "775Dual-VSTA",
> POS_FIX_LPIB),
> > > > > >  	SND_PCI_QUIRK(0x8086, 0x2503, "DG965OT AAD63733-203",
> > > > > POS_FIX_LPIB),
> > > > > > +	SND_PCI_QUIRK(0x8086, 0x2010, "Broadwell HDMI audio",
> > > > > POS_FIX_LPIB),
> > > > > >  	{}
> > > > > >  };
> > > > > >
> > > > > > --
> > > > > > 1.8.3.2
> > > > > >
> > > >
> >
> >
> > Regards,
> > Libin
> >

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Thu, 8 May 2014 06:28:17 +0000,
Yang, Libin wrote:
> 
> Hi Takashi,
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de]
> > Sent: Thursday, May 8, 2014 2:20 PM
> > To: Yang, Libin
> > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI
> > Audio
> > 
> > At Thu, 8 May 2014 06:13:31 +0000,
> > Yang, Libin wrote:
> > >
> > > Hi Takashi,
> > >
> > > > -----Original Message-----
> > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > Sent: Thursday, May 8, 2014 1:51 PM
> > > > To: Yang, Libin
> > > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > > HDMI Audio
> > > >
> > > > At Thu, 8 May 2014 05:48:04 +0000,
> > > > Yang, Libin wrote:
> > > > >
> > > > > Hi Takashi,
> > > > >
> > > > > I checked the wallclock counter. The counter is OK. But it failed
> > > > > to correct
> > > > the position.
> > > >
> > > > So, how wrong the position buffer is?  Is the problem intermittent?
> > > > Please elaborate more.
> > >
> > > The issue is the position is almost always inaccurate. You will hear there is
> > intermittent noise in the sound. And the sound is played faster than it should
> > be.
> > >
> > > The following message is what I got from dmesg:
> > >
> > > [ 73.278117] snd_hda_intel 0000:00:03.0: IRQ timing workaround is
> > activated for card #0. Suggest a bigger bdl_pos_adj.
> > > [ 73.528575] snd_hda_intel 0000:00:03.0: Unstable LPIB (26240 >=
> > > 24064); disabling LPIB delay counting
> > >
> > > Do you think the print of wallclk and position information in the function
> > azx_position_ok() is useful to you? If yes, I will add debug code to print the
> > info.
> > 
> > It'd better to have the raw values of posbuf, lpib and wallclock for further
> > analysis, yes.
> > 
> > BTW, did you try non-snoop mode via snoop=0 option?
> 
> I haven't tried non-snoop. Do I use `modprobe snd-hda-intel snoop=0` to use non-snoop mode?

Yes.

Takashi

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Yang, Libin]

Hi Takashi,

I tested the non-snoop mode. It's worse than snoop mode. Only noise can be heard if using non-snoop mode.

I add the print in the function azx_position_ok(). The below is the dmesg:
[  119.509631] <0>posbuf: 26368, lpib: 16320, wallclk: 2330325
[  119.509674] snd_hda_intel 0000:00:03.0: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj.
[  119.509683] <0>posbuf: 26368, lpib: 16332, wallclk: 2331659
[  119.515467] <0>posbuf: 28224, lpib: 17444, wallclk: 2470504
[  119.523460] <0>posbuf: 30592, lpib: 18976, wallclk: 2662403
[  119.531431] <0>posbuf: 32128, lpib: 20508, wallclk: 2853751
[  119.594932] snd_hda_intel 0000:00:03.0: Unstable LPIB (20416 >= 16384); disabling LPIB delay counting
[  119.594940] <0>posbuf: 53120, lpib: 32708, wallclk: 4378574
[  119.680236] <0>posbuf: 14144, lpib: 49088, wallclk: 6426353
[  119.680268] <0>posbuf: 14208, lpib: 49096, wallclk: 6427176
[  119.687378] <0>posbuf: 15552, lpib: 50460, wallclk: 6597848
[  119.695391] <0>posbuf: 19776, lpib: 52000, wallclk: 6790194
[  119.765532] <0>posbuf: 42816, lpib: 65472, wallclk: 8474222
[  119.765558] <0>posbuf: 42880, lpib: 65476, wallclk: 8474886
[  119.771373] <0>posbuf: 43968, lpib: 1056, wallclk: 8614451
[  119.779343] <0>posbuf: 45824, lpib: 2588, wallclk: 8805772
[  119.787383] <0>posbuf: 63168, lpib: 4132, wallclk: 8998804
[  119.795365] <0>posbuf: 65472, lpib: 5664, wallclk: 9190453
[  119.803355] <0>posbuf: 1472, lpib: 7200, wallclk: 9382317
[  119.936141] <0>posbuf: 41272, lpib: 32704, wallclk: 12570283
[  120.021440] <0>posbuf: 1600, lpib: 49088, wallclk: 14618206
[  120.106744] <0>posbuf: 35584, lpib: 65472, wallclk: 16666259
[  120.192049] <0>posbuf: 59520, lpib: 16320, wallclk: 18714292
[  120.192083] <0>posbuf: 59584, lpib: 16328, wallclk: 18715146
[  120.199208] <0>posbuf: 60928, lpib: 17696, wallclk: 18886244
[  120.207186] <0>posbuf: 63360, lpib: 19228, wallclk: 19077747
[  120.215205] <0>posbuf: 64896, lpib: 20768, wallclk: 19270235
[  120.277352] <0>posbuf: 17472, lpib: 32704, wallclk: 20762304
[  120.362649] <0>posbuf: 51200, lpib: 49088, wallclk: 22810207
[  120.447951] <0>posbuf: 24128, lpib: 65472, wallclk: 24858211
[  120.533254] <0>posbuf: 50240, lpib: 16320, wallclk: 26906204
[  120.618557] <0>posbuf: 7872, lpib: 32704, wallclk: 28954206
[  120.703866] <0>posbuf: 34304, lpib: 49088, wallclk: 31002327
[  120.789162] <0>posbuf: 57216, lpib: 65472, wallclk: 33050211
[  120.874466] <0>posbuf: 21696, lpib: 16320, wallclk: 35098213
[  120.959775] <0>posbuf: 40896, lpib: 32704, wallclk: 37146356
[  121.045071] <0>posbuf: 65512, lpib: 49088, wallclk: 39194209
[  121.045105] <0>posbuf: 65512, lpib: 49096, wallclk: 39195098
[  121.050904] <0>posbuf: 1088, lpib: 50208, wallclk: 39334239
[  121.130373] <0>posbuf: 25672, lpib: 65472, wallclk: 41242241
[  121.130393] <0>posbuf: 25736, lpib: 65476, wallclk: 41242756
[  121.134894] <0>posbuf: 26568, lpib: 804, wallclk: 41350761
[  121.142891] <0>posbuf: 28104, lpib: 2340, wallclk: 41542772
[  121.150843] <0>posbuf: 29640, lpib: 3868, wallclk: 41733690
[  121.158872] <0>posbuf: 31816, lpib: 5408, wallclk: 41926445
[  121.300979] <0>posbuf: 5184, lpib: 32704, wallclk: 45338238
[  121.386301] <0>posbuf: 39616, lpib: 49092, wallclk: 47386704
[  121.471582] <0>posbuf: 63168, lpib: 65472, wallclk: 49434209
[  121.471617] <0>posbuf: 63232, lpib: 65480, wallclk: 49435075
[  121.478756] <0>posbuf: 1152, lpib: 1312, wallclk: 49606462
[  121.556891] <0>posbuf: 25408, lpib: 16320, wallclk: 51482305
[  121.556926] <0>posbuf: 25472, lpib: 16328, wallclk: 51483213
[  121.562750] <0>posbuf: 26560, lpib: 17448, wallclk: 51623001
[  121.570720] <0>posbuf: 28096, lpib: 18976, wallclk: 51814375
[  121.578734] <0>posbuf: 32128, lpib: 20516, wallclk: 52006750
[  121.586740] <0>posbuf: 33664, lpib: 22052, wallclk: 52198989
[  121.727492] <0>posbuf: 4032, lpib: 49088, wallclk: 55578261
[  121.812793] <0>posbuf: 33600, lpib: 65472, wallclk: 57626206
[  121.898104] <0>posbuf: 61632, lpib: 16320, wallclk: 59674370
[  121.898141] <0>posbuf: 61632, lpib: 16328, wallclk: 59675331
[  121.902593] <0>posbuf: 62464, lpib: 17184, wallclk: 59782193
[  121.910606] <0>posbuf: 2816, lpib: 18724, wallclk: 59974590
[  121.983404] <0>posbuf: 28096, lpib: 32704, wallclk: 61722303
[  121.983445] <0>posbuf: 28096, lpib: 32712, wallclk: 61723274
[  121.990560] <0>posbuf: 29504, lpib: 34080, wallclk: 61894156
[  121.998546] <0>posbuf: 34624, lpib: 35612, wallclk: 62085935
[  122.068702] <0>posbuf: 49600, lpib: 49088, wallclk: 63770204
[  122.154009] <0>posbuf: 15488, lpib: 65472, wallclk: 65818332
[  122.154046] <0>posbuf: 15552, lpib: 65480, wallclk: 65819256
[  122.158520] <0>posbuf: 16384, lpib: 804, wallclk: 65926628
[  122.239309] <0>posbuf: 45760, lpib: 16320, wallclk: 67866282
[  122.239331] <0>posbuf: 45760, lpib: 16324, wallclk: 67866855
[  122.246459] <0>posbuf: 47168, lpib: 17692, wallclk: 68037996
[  122.254452] <0>posbuf: 52480, lpib: 19228, wallclk: 68229867
[  122.324608] <0>posbuf: 16192, lpib: 32704, wallclk: 69914215
[  122.324644] <0>posbuf: 16256, lpib: 32712, wallclk: 69915098
[  122.330453] <0>posbuf: 19264, lpib: 33828, wallclk: 70054572
[  122.409916] <0>posbuf: 47744, lpib: 49088, wallclk: 71962318
[  122.409950] <0>posbuf: 47808, lpib: 49096, wallclk: 71963172
[  122.414421] <0>posbuf: 48640, lpib: 49952, wallclk: 72070480
[  122.422413] <0>posbuf: 50496, lpib: 51488, wallclk: 72262373
[  122.495215] <0>posbuf: 4544, lpib: 65472, wallclk: 74010232
[  122.580516] <0>posbuf: 30144, lpib: 16320, wallclk: 76058218
[  122.580549] <0>posbuf: 30144, lpib: 16328, wallclk: 76059056
[  122.586330] <0>posbuf: 31296, lpib: 17436, wallclk: 76197834
[  122.594354] <0>posbuf: 34304, lpib: 18976, wallclk: 76390435
[  122.665824] <0>posbuf: 48000, lpib: 32704, wallclk: 78106302
[  122.665859] <0>posbuf: 48064, lpib: 32712, wallclk: 78107204
[  122.670317] <0>posbuf: 49152, lpib: 33568, wallclk: 78214218
[  122.751125] <0>posbuf: 10368, lpib: 49088, wallclk: 80154285
[  122.751157] <0>posbuf: 10432, lpib: 49096, wallclk: 80155098
[  122.758292] <0>posbuf: 11776, lpib: 50464, wallclk: 80326335
[  122.766288] <0>posbuf: 13312, lpib: 52000, wallclk: 80518371
[  122.774277] <0>posbuf: 15616, lpib: 53536, wallclk: 80710186
[  122.782262] <0>posbuf: 17152, lpib: 55068, wallclk: 80901852
[  122.921726] <0>posbuf: 55680, lpib: 16320, wallclk: 84250213
[  123.007035] <0>posbuf: 20928, lpib: 32704, wallclk: 86298342
[  123.092332] <0>posbuf: 45824, lpib: 49088, wallclk: 88346236
[  123.092347] <0>posbuf: 45824, lpib: 49092, wallclk: 88346635
[  123.098155] <0>posbuf: 48512, lpib: 50208, wallclk: 88486077
[  123.106141] <0>posbuf: 50048, lpib: 51740, wallclk: 88677794
[  123.177633] <0>posbuf: 12928, lpib: 65472, wallclk: 90394202
[  123.177664] <0>posbuf: 12928, lpib: 65476, wallclk: 90394982
[  123.182132] <0>posbuf: 13824, lpib: 800, wallclk: 90502214
[  123.190135] <0>posbuf: 15360, lpib: 2336, wallclk: 90694383
[  123.198168] <0>posbuf: 22400, lpib: 3880, wallclk: 90887194
[  123.262941] <0>posbuf: 41152, lpib: 16320, wallclk: 92442299
[  123.262975] <0>posbuf: 41152, lpib: 16328, wallclk: 92443159
[  123.270098] <0>posbuf: 46080, lpib: 17696, wallclk: 92614190
[  123.278088] <0>posbuf: 53120, lpib: 19232, wallclk: 92806002
[  123.348238] <0>posbuf: 7808, lpib: 32704, wallclk: 94490195
[  123.433540] <0>posbuf: 41664, lpib: 49088, wallclk: 96538196
[  123.433574] <0>posbuf: 41728, lpib: 49096, wallclk: 96539044
[  123.438020] <0>posbuf: 42560, lpib: 49948, wallclk: 96645775
[  123.446056] <0>posbuf: 44096, lpib: 51492, wallclk: 96838682
[  123.454017] <0>posbuf: 45632, lpib: 53020, wallclk: 97029796
[  123.462035] <0>posbuf: 49536, lpib: 54560, wallclk: 97222323
[  123.604151] <0>posbuf: 26624, lpib: 16320, wallclk: 100634303

The aplay output is:
Playing WAVE '/home/younglee/wavs/48KHz.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Plug PCM: Hardware PCM card 0 'HDA Intel HDMI' device 7 subdevice 0
Its setup is:
  stream       : PLAYBACK
  access       : RW_INTERLEAVED
  format       : S16_LE
  subformat    : STD
  channels     : 2
  rate         : 48000
  exact rate   : 48000 (48000/1)
  msbits       : 16
  buffer_size  : 16384
  period_size  : 4096
  period_time  : 85333
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 4096
  period_event : 0
  start_threshold  : 16384
  stop_threshold   : 16384
  silence_threshold: 0
  silence_size : 0
  boundary     : 4611686018427387904
  appl_ptr     : 0
  hw_ptr       : 0
Aborted by signal Interrupt...

Regards,
Libin

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Thursday, May 8, 2014 2:40 PM
> To: Yang, Libin
> Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI
> Audio
> 
> At Thu, 8 May 2014 06:28:17 +0000,
> Yang, Libin wrote:
> >
> > Hi Takashi,
> >
> > > -----Original Message-----
> > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > Sent: Thursday, May 8, 2014 2:20 PM
> > > To: Yang, Libin
> > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > HDMI Audio
> > >
> > > At Thu, 8 May 2014 06:13:31 +0000,
> > > Yang, Libin wrote:
> > > >
> > > > Hi Takashi,
> > > >
> > > > > -----Original Message-----
> > > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > > Sent: Thursday, May 8, 2014 1:51 PM
> > > > > To: Yang, Libin
> > > > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis
> > > > > Bossart
> > > > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > > > HDMI Audio
> > > > >
> > > > > At Thu, 8 May 2014 05:48:04 +0000, Yang, Libin wrote:
> > > > > >
> > > > > > Hi Takashi,
> > > > > >
> > > > > > I checked the wallclock counter. The counter is OK. But it
> > > > > > failed to correct
> > > > > the position.
> > > > >
> > > > > So, how wrong the position buffer is?  Is the problem intermittent?
> > > > > Please elaborate more.
> > > >
> > > > The issue is the position is almost always inaccurate. You will
> > > > hear there is
> > > intermittent noise in the sound. And the sound is played faster than
> > > it should be.
> > > >
> > > > The following message is what I got from dmesg:
> > > >
> > > > [ 73.278117] snd_hda_intel 0000:00:03.0: IRQ timing workaround is
> > > activated for card #0. Suggest a bigger bdl_pos_adj.
> > > > [ 73.528575] snd_hda_intel 0000:00:03.0: Unstable LPIB (26240 >=
> > > > 24064); disabling LPIB delay counting
> > > >
> > > > Do you think the print of wallclk and position information in the
> > > > function
> > > azx_position_ok() is useful to you? If yes, I will add debug code to
> > > print the info.
> > >
> > > It'd better to have the raw values of posbuf, lpib and wallclock for
> > > further analysis, yes.
> > >
> > > BTW, did you try non-snoop mode via snoop=0 option?
> >
> > I haven't tried non-snoop. Do I use `modprobe snd-hda-intel snoop=0` to
> use non-snoop mode?
> 
> Yes.
> 
> Takashi

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[David Henningsson]

On 2014-05-08 09:58, Yang, Libin wrote:
> Hi Takashi,
>
> I tested the non-snoop mode. It's worse than snoop mode. Only noise can be heard if using non-snoop mode.
>
> I add the print in the function azx_position_ok(). The below is the dmesg:
> [  119.509631] <0>posbuf: 26368, lpib: 16320, wallclk: 2330325
> [  119.509674] snd_hda_intel 0000:00:03.0: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj.
> [  119.509683] <0>posbuf: 26368, lpib: 16332, wallclk: 2331659
> [  119.515467] <0>posbuf: 28224, lpib: 17444, wallclk: 2470504
> [  119.523460] <0>posbuf: 30592, lpib: 18976, wallclk: 2662403
> [  119.531431] <0>posbuf: 32128, lpib: 20508, wallclk: 2853751
> [  119.594932] snd_hda_intel 0000:00:03.0: Unstable LPIB (20416 >= 16384); disabling LPIB delay counting

This looks quite bad - is it not a hardware bug if LPIB > CBL (CBL 
should be 16384 in this case)?


-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Lin, Mengdong]

Hi,

We found the Broadwell HDMI audio regression is introduced by this patch:

commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd
Author: Anssi Hannula <anssi.hannula@iki.fi>
Date: Tue Apr 8 12:36:42 2014 +0300
ALSA: hda - Do not assign streams in reverse order

We'll further check the root cause.
Since this patch seems only affect the stream ID. Actually Intel GPU tool only find the stream ID is changed by this patch.

In addition, Haswell HDMI audio is not affected and works well. It seems there is HW behavior difference between HSW and BDW.

Thanks
Mengdong

> -----Original Message-----
> From: David Henningsson [mailto:david.henningsson@canonical.com]
> Sent: Friday, May 09, 2014 12:06 AM
> To: Yang, Libin; Takashi Iwai
> Cc: Lin, Mengdong; alsa-devel@alsa-project.org; Pierre-Louis Bossart
> Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> HDMI Audio
> 
> 
> 
> On 2014-05-08 09:58, Yang, Libin wrote:
> > Hi Takashi,
> >
> > I tested the non-snoop mode. It's worse than snoop mode. Only noise can be
> heard if using non-snoop mode.
> >
> > I add the print in the function azx_position_ok(). The below is the dmesg:
> > [  119.509631] <0>posbuf: 26368, lpib: 16320, wallclk: 2330325 [
> > 119.509674] snd_hda_intel 0000:00:03.0: IRQ timing workaround is
> activated for card #0. Suggest a bigger bdl_pos_adj.
> > [  119.509683] <0>posbuf: 26368, lpib: 16332, wallclk: 2331659 [
> > 119.515467] <0>posbuf: 28224, lpib: 17444, wallclk: 2470504 [
> > 119.523460] <0>posbuf: 30592, lpib: 18976, wallclk: 2662403 [
> > 119.531431] <0>posbuf: 32128, lpib: 20508, wallclk: 2853751 [
> > 119.594932] snd_hda_intel 0000:00:03.0: Unstable LPIB (20416 >=
> > 16384); disabling LPIB delay counting
> 
> This looks quite bad - is it not a hardware bug if LPIB > CBL (CBL should be
> 16384 in this case)?
> 
> 
> --
> David Henningsson, Canonical Ltd.
> https://launchpad.net/~diwic

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Fri, 9 May 2014 10:08:19 +0000,
Lin, Mengdong wrote:
> 
> Hi,
> 
> We found the Broadwell HDMI audio regression is introduced by this patch:
> 
> commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd
> Author: Anssi Hannula <anssi.hannula@iki.fi>
> Date: Tue Apr 8 12:36:42 2014 +0300
> ALSA: hda - Do not assign streams in reverse order
> 
> We'll further check the root cause.
> Since this patch seems only affect the stream ID. Actually Intel GPU tool only find the stream ID is changed by this patch.
> 
> In addition, Haswell HDMI audio is not affected and works well. It seems there is HW behavior difference between HSW and BDW.

Thanks for spotting out!

This sounds like a weird hardware bug of BDW.  If any, we'd need to
introduce a flag indicating flipping this  lookup behavior depending
on the chip.


Takashi

> 
> Thanks
> Mengdong
> 
> > -----Original Message-----
> > From: David Henningsson [mailto:david.henningsson@canonical.com]
> > Sent: Friday, May 09, 2014 12:06 AM
> > To: Yang, Libin; Takashi Iwai
> > Cc: Lin, Mengdong; alsa-devel@alsa-project.org; Pierre-Louis Bossart
> > Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > HDMI Audio
> > 
> > 
> > 
> > On 2014-05-08 09:58, Yang, Libin wrote:
> > > Hi Takashi,
> > >
> > > I tested the non-snoop mode. It's worse than snoop mode. Only noise can be
> > heard if using non-snoop mode.
> > >
> > > I add the print in the function azx_position_ok(). The below is the dmesg:
> > > [  119.509631] <0>posbuf: 26368, lpib: 16320, wallclk: 2330325 [
> > > 119.509674] snd_hda_intel 0000:00:03.0: IRQ timing workaround is
> > activated for card #0. Suggest a bigger bdl_pos_adj.
> > > [  119.509683] <0>posbuf: 26368, lpib: 16332, wallclk: 2331659 [
> > > 119.515467] <0>posbuf: 28224, lpib: 17444, wallclk: 2470504 [
> > > 119.523460] <0>posbuf: 30592, lpib: 18976, wallclk: 2662403 [
> > > 119.531431] <0>posbuf: 32128, lpib: 20508, wallclk: 2853751 [
> > > 119.594932] snd_hda_intel 0000:00:03.0: Unstable LPIB (20416 >=
> > > 16384); disabling LPIB delay counting
> > 
> > This looks quite bad - is it not a hardware bug if LPIB > CBL (CBL should be
> > 16384 in this case)?
> > 
> > 
> > --
> > David Henningsson, Canonical Ltd.
> > https://launchpad.net/~diwic
> 

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Lin, Mengdong]

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Friday, May 09, 2014 6:20 PM
> To: Lin, Mengdong
> Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> alsa-devel@alsa-project.org; Pierre-Louis Bossart
> Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> HDMI Audio
> 
> At Fri, 9 May 2014 10:08:19 +0000,
> Lin, Mengdong wrote:
> >
> > Hi,
> >
> > We found the Broadwell HDMI audio regression is introduced by this patch:
> >
> > commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd
> > Author: Anssi Hannula <anssi.hannula@iki.fi>
> > Date: Tue Apr 8 12:36:42 2014 +0300
> > ALSA: hda - Do not assign streams in reverse order
> >
> > We'll further check the root cause.
> > Since this patch seems only affect the stream ID. Actually Intel GPU tool only
> find the stream ID is changed by this patch.
> >
> > In addition, Haswell HDMI audio is not affected and works well. It seems
> there is HW behavior difference between HSW and BDW.
> 
> Thanks for spotting out!
> 
> This sounds like a weird hardware bug of BDW.  If any, we'd need to introduce
> a flag indicating flipping this  lookup behavior depending on the chip.

In the display HD-A controller of HSW/BDW, there are 3 sets of stream descriptors registers which controls the DMA engines to transfer audio data over HD-A link:
set #0: 0x80 ~ 0x9c SD0CTL ~ SD0BDPU
set #1: 0xa0 ~ 0xbc SD1CTL ~ SD1BDPU
set #2: 0xc0 ~ 0xdc SD2CTL ~ SD2BDPU

Test shows that
On HSW, DMA update on all 3 sets of registers are okay.
On BDW, DMA update on set #1 and #2 are okay, but is buggy on set #0. Since the three sets of registers have the same definition according to spec and driver behavior is also same, it seems to be a HW issue.

Maybe we'll have to use the original reverse lookup order for BDW HDMI/DP audio.

Thanks
Mengdong

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Mon, 12 May 2014 08:22:13 +0000,
Lin, Mengdong wrote:
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de]
> > Sent: Friday, May 09, 2014 6:20 PM
> > To: Lin, Mengdong
> > Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> > alsa-devel@alsa-project.org; Pierre-Louis Bossart
> > Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > HDMI Audio
> > 
> > At Fri, 9 May 2014 10:08:19 +0000,
> > Lin, Mengdong wrote:
> > >
> > > Hi,
> > >
> > > We found the Broadwell HDMI audio regression is introduced by this patch:
> > >
> > > commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd
> > > Author: Anssi Hannula <anssi.hannula@iki.fi>
> > > Date: Tue Apr 8 12:36:42 2014 +0300
> > > ALSA: hda - Do not assign streams in reverse order
> > >
> > > We'll further check the root cause.
> > > Since this patch seems only affect the stream ID. Actually Intel GPU tool only
> > find the stream ID is changed by this patch.
> > >
> > > In addition, Haswell HDMI audio is not affected and works well. It seems
> > there is HW behavior difference between HSW and BDW.
> > 
> > Thanks for spotting out!
> > 
> > This sounds like a weird hardware bug of BDW.  If any, we'd need to introduce
> > a flag indicating flipping this  lookup behavior depending on the chip.
> 
> In the display HD-A controller of HSW/BDW, there are 3 sets of stream descriptors registers which controls the DMA engines to transfer audio data over HD-A link:
> set #0: 0x80 ~ 0x9c SD0CTL ~ SD0BDPU
> set #1: 0xa0 ~ 0xbc SD1CTL ~ SD1BDPU
> set #2: 0xc0 ~ 0xdc SD2CTL ~ SD2BDPU
> 
> Test shows that
> On HSW, DMA update on all 3 sets of registers are okay.
> On BDW, DMA update on set #1 and #2 are okay, but is buggy on set #0. Since the three sets of registers have the same definition according to spec and driver behavior is also same, it seems to be a HW issue.
> 
> Maybe we'll have to use the original reverse lookup order for BDW HDMI/DP audio.

I wonder what if you run three streams.  Is the set#0 always broken,
or broken only when used alone?  In the former case, the fix would to
mask the first slot.  In the latter case, back to reverse assignment
would work around it.


Takashi

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Lin, Mengdong]

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Monday, May 12, 2014 4:31 PM
> To: Lin, Mengdong
> Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> alsa-devel@alsa-project.org; Pierre-Louis Bossart
> Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> HDMI Audio
> 
> At Mon, 12 May 2014 08:22:13 +0000,
> Lin, Mengdong wrote:
> >
> > > -----Original Message-----
> > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > Sent: Friday, May 09, 2014 6:20 PM
> > > To: Lin, Mengdong
> > > Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> > > alsa-devel@alsa-project.org; Pierre-Louis Bossart
> > > Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on
> > > Broadwell HDMI Audio
> > >
> > > At Fri, 9 May 2014 10:08:19 +0000,
> > > Lin, Mengdong wrote:
> > > >
> > > > Hi,
> > > >
> > > > We found the Broadwell HDMI audio regression is introduced by this
> patch:
> > > >
> > > > commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd
> > > > Author: Anssi Hannula <anssi.hannula@iki.fi>
> > > > Date: Tue Apr 8 12:36:42 2014 +0300
> > > > ALSA: hda - Do not assign streams in reverse order
> > > >
> > > > We'll further check the root cause.
> > > > Since this patch seems only affect the stream ID. Actually Intel
> > > > GPU tool only
> > > find the stream ID is changed by this patch.
> > > >
> > > > In addition, Haswell HDMI audio is not affected and works well. It
> > > > seems
> > > there is HW behavior difference between HSW and BDW.
> > >
> > > Thanks for spotting out!
> > >
> > > This sounds like a weird hardware bug of BDW.  If any, we'd need to
> > > introduce a flag indicating flipping this  lookup behavior depending on the
> chip.
> >
> > In the display HD-A controller of HSW/BDW, there are 3 sets of stream
> descriptors registers which controls the DMA engines to transfer audio data
> over HD-A link:
> > set #0: 0x80 ~ 0x9c SD0CTL ~ SD0BDPU
> > set #1: 0xa0 ~ 0xbc SD1CTL ~ SD1BDPU
> > set #2: 0xc0 ~ 0xdc SD2CTL ~ SD2BDPU
> >
> > Test shows that
> > On HSW, DMA update on all 3 sets of registers are okay.
> > On BDW, DMA update on set #1 and #2 are okay, but is buggy on set #0.
> Since the three sets of registers have the same definition according to spec and
> driver behavior is also same, it seems to be a HW issue.
> >
> > Maybe we'll have to use the original reverse lookup order for BDW HDMI/DP
> audio.
> 
> I wonder what if you run three streams.  Is the set#0 always broken, or broken
> only when used alone?  In the former case, the fix would to mask the first slot.
> In the latter case, back to reverse assignment would work around it.

The set#0 is always broken, when I run single or two streams at the same time. 
And when running two streams, there is no difference if the audio driver choose set#0 or #1 at first.

Is it okay to introduce a flag "disabled" to struct azx_dev? 
If this flag is set, the azx_dev slot is masked.

Thanks
Mengdong

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Mon, 12 May 2014 09:46:07 +0000,
Lin, Mengdong wrote:
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de]
> > Sent: Monday, May 12, 2014 4:31 PM
> > To: Lin, Mengdong
> > Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> > alsa-devel@alsa-project.org; Pierre-Louis Bossart
> > Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > HDMI Audio
> > 
> > At Mon, 12 May 2014 08:22:13 +0000,
> > Lin, Mengdong wrote:
> > >
> > > > -----Original Message-----
> > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > Sent: Friday, May 09, 2014 6:20 PM
> > > > To: Lin, Mengdong
> > > > Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> > > > alsa-devel@alsa-project.org; Pierre-Louis Bossart
> > > > Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on
> > > > Broadwell HDMI Audio
> > > >
> > > > At Fri, 9 May 2014 10:08:19 +0000,
> > > > Lin, Mengdong wrote:
> > > > >
> > > > > Hi,
> > > > >
> > > > > We found the Broadwell HDMI audio regression is introduced by this
> > patch:
> > > > >
> > > > > commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd
> > > > > Author: Anssi Hannula <anssi.hannula@iki.fi>
> > > > > Date: Tue Apr 8 12:36:42 2014 +0300
> > > > > ALSA: hda - Do not assign streams in reverse order
> > > > >
> > > > > We'll further check the root cause.
> > > > > Since this patch seems only affect the stream ID. Actually Intel
> > > > > GPU tool only
> > > > find the stream ID is changed by this patch.
> > > > >
> > > > > In addition, Haswell HDMI audio is not affected and works well. It
> > > > > seems
> > > > there is HW behavior difference between HSW and BDW.
> > > >
> > > > Thanks for spotting out!
> > > >
> > > > This sounds like a weird hardware bug of BDW.  If any, we'd need to
> > > > introduce a flag indicating flipping this  lookup behavior depending on the
> > chip.
> > >
> > > In the display HD-A controller of HSW/BDW, there are 3 sets of stream
> > descriptors registers which controls the DMA engines to transfer audio data
> > over HD-A link:
> > > set #0: 0x80 ~ 0x9c SD0CTL ~ SD0BDPU
> > > set #1: 0xa0 ~ 0xbc SD1CTL ~ SD1BDPU
> > > set #2: 0xc0 ~ 0xdc SD2CTL ~ SD2BDPU
> > >
> > > Test shows that
> > > On HSW, DMA update on all 3 sets of registers are okay.
> > > On BDW, DMA update on set #1 and #2 are okay, but is buggy on set #0.
> > Since the three sets of registers have the same definition according to spec and
> > driver behavior is also same, it seems to be a HW issue.
> > >
> > > Maybe we'll have to use the original reverse lookup order for BDW HDMI/DP
> > audio.
> > 
> > I wonder what if you run three streams.  Is the set#0 always broken, or broken
> > only when used alone?  In the former case, the fix would to mask the first slot.
> > In the latter case, back to reverse assignment would work around it.
> 
> The set#0 is always broken, when I run single or two streams at the same time. 
> And when running two streams, there is no difference if the audio driver choose set#0 or #1 at first.
> 
> Is it okay to introduce a flag "disabled" to struct azx_dev? 
> If this flag is set, the azx_dev slot is masked.

You can just keep azx_dev->opened flag set at initialization time.


Takashi

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Lin, Mengdong]

Hi Takashi,

I submitted two patches to mask the buggy DMA0 of Broadwell display controller. Please review.

[PATCH 1/2] ALSA: hda - allow to mask a buggy stream DMA by setting it as opened
[PATCH 2/2] ALSA: hda - mask buggy stream DMA0 for Broadwell display controller

Thanks again
Mengdong

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Monday, May 12, 2014 5:52 PM
> To: Lin, Mengdong
> Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> alsa-devel@alsa-project.org; Pierre-Louis Bossart
> Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> HDMI Audio
> 
> At Mon, 12 May 2014 09:46:07 +0000,
> Lin, Mengdong wrote:
> >
> > > -----Original Message-----
> > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > Sent: Monday, May 12, 2014 4:31 PM
> > > To: Lin, Mengdong
> > > Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> > > alsa-devel@alsa-project.org; Pierre-Louis Bossart
> > > Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on
> > > Broadwell HDMI Audio
> > >
> > > At Mon, 12 May 2014 08:22:13 +0000,
> > > Lin, Mengdong wrote:
> > > >
> > > > > -----Original Message-----
> > > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > > Sent: Friday, May 09, 2014 6:20 PM
> > > > > To: Lin, Mengdong
> > > > > Cc: David Henningsson; Yang, Libin; anssi.hannula@iki.fi;
> > > > > alsa-devel@alsa-project.org; Pierre-Louis Bossart
> > > > > Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB
> > > > > on Broadwell HDMI Audio
> > > > >
> > > > > At Fri, 9 May 2014 10:08:19 +0000, Lin, Mengdong wrote:
> > > > > >
> > > > > > Hi,
> > > > > >
> > > > > > We found the Broadwell HDMI audio regression is introduced by
> > > > > > this
> > > patch:
> > > > > >
> > > > > > commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd
> > > > > > Author: Anssi Hannula <anssi.hannula@iki.fi>
> > > > > > Date: Tue Apr 8 12:36:42 2014 +0300
> > > > > > ALSA: hda - Do not assign streams in reverse order
> > > > > >
> > > > > > We'll further check the root cause.
> > > > > > Since this patch seems only affect the stream ID. Actually
> > > > > > Intel GPU tool only
> > > > > find the stream ID is changed by this patch.
> > > > > >
> > > > > > In addition, Haswell HDMI audio is not affected and works
> > > > > > well. It seems
> > > > > there is HW behavior difference between HSW and BDW.
> > > > >
> > > > > Thanks for spotting out!
> > > > >
> > > > > This sounds like a weird hardware bug of BDW.  If any, we'd need
> > > > > to introduce a flag indicating flipping this  lookup behavior
> > > > > depending on the
> > > chip.
> > > >
> > > > In the display HD-A controller of HSW/BDW, there are 3 sets of
> > > > stream
> > > descriptors registers which controls the DMA engines to transfer
> > > audio data over HD-A link:
> > > > set #0: 0x80 ~ 0x9c SD0CTL ~ SD0BDPU set #1: 0xa0 ~ 0xbc SD1CTL ~
> > > > SD1BDPU set #2: 0xc0 ~ 0xdc SD2CTL ~ SD2BDPU
> > > >
> > > > Test shows that
> > > > On HSW, DMA update on all 3 sets of registers are okay.
> > > > On BDW, DMA update on set #1 and #2 are okay, but is buggy on set #0.
> > > Since the three sets of registers have the same definition according
> > > to spec and driver behavior is also same, it seems to be a HW issue.
> > > >
> > > > Maybe we'll have to use the original reverse lookup order for BDW
> > > > HDMI/DP
> > > audio.
> > >
> > > I wonder what if you run three streams.  Is the set#0 always broken,
> > > or broken only when used alone?  In the former case, the fix would to
> mask the first slot.
> > > In the latter case, back to reverse assignment would work around it.
> >
> > The set#0 is always broken, when I run single or two streams at the same
> time.
> > And when running two streams, there is no difference if the audio driver
> choose set#0 or #1 at first.
> >
> > Is it okay to introduce a flag "disabled" to struct azx_dev?
> > If this flag is set, the azx_dev slot is masked.
> 
> You can just keep azx_dev->opened flag set at initialization time.
> 
> 
> Takashi

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Tue, 13 May 2014 04:37:18 +0000,
Lin, Mengdong wrote:
> 
> Hi Takashi,
> 
> I submitted two patches to mask the buggy DMA0 of Broadwell display controller. Please review.
> 
> [PATCH 1/2] ALSA: hda - allow to mask a buggy stream DMA by setting it as opened
> [PATCH 2/2] ALSA: hda - mask buggy stream DMA0 for Broadwell display controller

It can be just simple like the patch below.  This is rather a
tentative workaround.  If the hardware (or the corresponding part in
the graphics driver) is fixed, we can get rid of it easily.  So, just
keep the change as small and simple as possible.


Takashi

---
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index b540ad71eb0d..2c54629d62d1 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1367,6 +1367,12 @@ static int azx_first_init(struct azx *chip)
 	/* initialize streams */
 	azx_init_stream(chip);
 
+	/* workaround for Broadwell HDMI: the first stream is broken,
+	 * so mask it by keeping it as if opened
+	 */
+	if (pci->vendor == 0x8086 && pci->device == 0x160c)
+		chip->azx_dev[0].opened = 1;
+
 	/* initialize chip */
 	azx_init_pci(chip);
 	azx_init_chip(chip, (probe_only[dev] & 2) == 0);

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Lin, Mengdong]

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Tuesday, May 13, 2014 3:20 PM

> It can be just simple like the patch below.  This is rather a tentative
> workaround.  If the hardware (or the corresponding part in the graphics driver)
> is fixed, we can get rid of it easily.  So, just keep the change as small and
> simple as possible.
> 
> 
> Takashi
> 
> ---
> diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index
> b540ad71eb0d..2c54629d62d1 100644
> --- a/sound/pci/hda/hda_intel.c
> +++ b/sound/pci/hda/hda_intel.c
> @@ -1367,6 +1367,12 @@ static int azx_first_init(struct azx *chip)
>  	/* initialize streams */
>  	azx_init_stream(chip);
> 
> +	/* workaround for Broadwell HDMI: the first stream is broken,
> +	 * so mask it by keeping it as if opened
> +	 */
> +	if (pci->vendor == 0x8086 && pci->device == 0x160c)
> +		chip->azx_dev[0].opened = 1;
> +
>  	/* initialize chip */
>  	azx_init_pci(chip);
>  	azx_init_chip(chip, (probe_only[dev] & 2) == 0);


Hi Takashi,

I revised the patch as you suggested. Hope we'll have a better solution for Broadwell soon.

Thanks
Mengdong

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Pierre-Louis Bossart]

On 5/9/14, 5:08 AM, Lin, Mengdong wrote:
> Hi,
>
> We found the Broadwell HDMI audio regression is introduced by this patch:
>
> commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd
> Author: Anssi Hannula <anssi.hannula@iki.fi>
> Date: Tue Apr 8 12:36:42 2014 +0300
> ALSA: hda - Do not assign streams in reverse order
>
> We'll further check the root cause.
> Since this patch seems only affect the stream ID. Actually Intel GPU tool only find the stream ID is changed by this patch.
>
> In addition, Haswell HDMI audio is not affected and works well. It seems there is HW behavior difference between HSW and BDW.

It's unlikely that the wallclock is the issue here. LPIB and wallclock 
only make sense for the short link to the GPU, where the data is 
reshuffled. It'd look into how the audio data is inserted in the HDMI 
frame, the fact that the behavior is linked to a channel order or stream 
ID points to GPU-level configuration, not a counter issue at the HDAudio 
controller level.
-Pierre

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Lin, Mengdong]

Hi Takashi,

Is it possible to accept this patch as a quick fix?

It seems that a driver regression triggers this issue, since we don't have this problem two weeks ago.
We're still trying to locate the regression and checking the root cause. 

This patch could avoid audio degradation atm before we have a better solution.

Thanks
Mengdong

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@suse.de]
> Sent: Thursday, May 08, 2014 2:40 PM
> To: Yang, Libin
> Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio
> 
> At Thu, 8 May 2014 06:28:17 +0000,
> Yang, Libin wrote:
> >
> > Hi Takashi,
> >
> > > -----Original Message-----
> > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > Sent: Thursday, May 8, 2014 2:20 PM
> > > To: Yang, Libin
> > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > HDMI Audio
> > >
> > > At Thu, 8 May 2014 06:13:31 +0000,
> > > Yang, Libin wrote:
> > > >
> > > > Hi Takashi,
> > > >
> > > > > -----Original Message-----
> > > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > > Sent: Thursday, May 8, 2014 1:51 PM
> > > > > To: Yang, Libin
> > > > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis
> > > > > Bossart
> > > > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > > > HDMI Audio
> > > > >
> > > > > At Thu, 8 May 2014 05:48:04 +0000, Yang, Libin wrote:
> > > > > >
> > > > > > Hi Takashi,
> > > > > >
> > > > > > I checked the wallclock counter. The counter is OK. But it
> > > > > > failed to correct
> > > > > the position.
> > > > >
> > > > > So, how wrong the position buffer is?  Is the problem intermittent?
> > > > > Please elaborate more.
> > > >
> > > > The issue is the position is almost always inaccurate. You will
> > > > hear there is
> > > intermittent noise in the sound. And the sound is played faster than
> > > it should be.
> > > >
> > > > The following message is what I got from dmesg:
> > > >
> > > > [ 73.278117] snd_hda_intel 0000:00:03.0: IRQ timing workaround is
> > > activated for card #0. Suggest a bigger bdl_pos_adj.
> > > > [ 73.528575] snd_hda_intel 0000:00:03.0: Unstable LPIB (26240 >=
> > > > 24064); disabling LPIB delay counting
> > > >
> > > > Do you think the print of wallclk and position information in the
> > > > function
> > > azx_position_ok() is useful to you? If yes, I will add debug code to
> > > print the info.
> > >
> > > It'd better to have the raw values of posbuf, lpib and wallclock for
> > > further analysis, yes.
> > >
> > > BTW, did you try non-snoop mode via snoop=0 option?
> >
> > I haven't tried non-snoop. Do I use `modprobe snd-hda-intel snoop=0` to use
> non-snoop mode?
> 
> Yes.
> 
> Takashi

Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio

[Takashi Iwai]

At Thu, 8 May 2014 09:37:13 +0000,
Lin, Mengdong wrote:
> 
> Hi Takashi,
> 
> Is it possible to accept this patch as a quick fix?

Well, the question is whether this is specific to this board, or it's
a generic issue of BDW HDMI controller.  In the latter case, the fix
is done in a wrong place.

> It seems that a driver regression triggers this issue, since we don't have this problem two weeks ago.
> We're still trying to locate the regression and checking the root cause. 

If it's a recent regression, I don't think it's good to apply a
bandaid.  There must be a cause (e.g. something changed in the
graphics side) to fix properly.

> This patch could avoid audio degradation atm before we have a better solution.

The workaround can be applied easily via module option, and the
machine isn't in the market yet.  So I see no point to hurry too much
for now...


thanks,

Takashi


> Thanks
> Mengdong
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de]
> > Sent: Thursday, May 08, 2014 2:40 PM
> > To: Yang, Libin
> > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio
> > 
> > At Thu, 8 May 2014 06:28:17 +0000,
> > Yang, Libin wrote:
> > >
> > > Hi Takashi,
> > >
> > > > -----Original Message-----
> > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > Sent: Thursday, May 8, 2014 2:20 PM
> > > > To: Yang, Libin
> > > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis Bossart
> > > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > > HDMI Audio
> > > >
> > > > At Thu, 8 May 2014 06:13:31 +0000,
> > > > Yang, Libin wrote:
> > > > >
> > > > > Hi Takashi,
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > > > Sent: Thursday, May 8, 2014 1:51 PM
> > > > > > To: Yang, Libin
> > > > > > Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Pierre-Louis
> > > > > > Bossart
> > > > > > Subject: Re: [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell
> > > > > > HDMI Audio
> > > > > >
> > > > > > At Thu, 8 May 2014 05:48:04 +0000, Yang, Libin wrote:
> > > > > > >
> > > > > > > Hi Takashi,
> > > > > > >
> > > > > > > I checked the wallclock counter. The counter is OK. But it
> > > > > > > failed to correct
> > > > > > the position.
> > > > > >
> > > > > > So, how wrong the position buffer is?  Is the problem intermittent?
> > > > > > Please elaborate more.
> > > > >
> > > > > The issue is the position is almost always inaccurate. You will
> > > > > hear there is
> > > > intermittent noise in the sound. And the sound is played faster than
> > > > it should be.
> > > > >
> > > > > The following message is what I got from dmesg:
> > > > >
> > > > > [ 73.278117] snd_hda_intel 0000:00:03.0: IRQ timing workaround is
> > > > activated for card #0. Suggest a bigger bdl_pos_adj.
> > > > > [ 73.528575] snd_hda_intel 0000:00:03.0: Unstable LPIB (26240 >=
> > > > > 24064); disabling LPIB delay counting
> > > > >
> > > > > Do you think the print of wallclk and position information in the
> > > > > function
> > > > azx_position_ok() is useful to you? If yes, I will add debug code to
> > > > print the info.
> > > >
> > > > It'd better to have the raw values of posbuf, lpib and wallclock for
> > > > further analysis, yes.
> > > >
> > > > BTW, did you try non-snoop mode via snoop=0 option?
> > >
> > > I haven't tried non-snoop. Do I use `modprobe snd-hda-intel snoop=0` to use
> > non-snoop mode?
> > 
> > Yes.
> > 
> > Takashi
>