Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Takashi Iwai]

On Fri, 12 Jan 2018 11:37:28 +0100,
Kumar, Abhijeet wrote:
> 
> > It's better, but doesn't guarantee that the node reached the given power 
> > state.  codec_read assures that the verb is sent and the codec gives the 
> > response.  But it means only the target state gets updated, and doesn't 
> > mean that the actual state reached.
> 
> Thanks Takashi for replying. I guess, I  should make use of return value from 
> codec_read and retry if power state is not set properly! I'll make those 
> changes and update again. And just wondering, how does hdmi_codec_prepare() 
> and hdmi_codec_complete() gurantee while powering up and down the afg ?

There are two power states in the codec node: the target and the
actual.  By setting the power state, the target is set, but the actual
state change may still take some time.  In such a case, you'd need to
wait until the actual state reaches.  See hda_sync_power_state() in
the hda legacy.


Takashi

Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Takashi Iwai]

On Fri, 12 Jan 2018 11:37:28 +0100,
Kumar, Abhijeet wrote:
> 
> > It's better, but doesn't guarantee that the node reached the given power 
> > state.  codec_read assures that the verb is sent and the codec gives the 
> > response.  But it means only the target state gets updated, and doesn't 
> > mean that the actual state reached.
> 
> Thanks Takashi for replying. I guess, I  should make use of return value from 
> codec_read and retry if power state is not set properly! I'll make those 
> changes and update again. And just wondering, how does hdmi_codec_prepare() 
> and hdmi_codec_complete() gurantee while powering up and down the afg ?

There are two power states in the codec node: the target and the
actual.  By setting the power state, the target is set, but the actual
state change may still take some time.  In such a case, you'd need to
wait until the actual state reaches.  See hda_sync_power_state() in
the hda legacy.


Takashi

RE: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Kumar, Abhijeet]

> It's better, but doesn't guarantee that the node reached the given power 
> state.  codec_read assures that the verb is sent and the codec gives the 
> response.  But it means only the target state gets updated, and doesn't mean 
> that the actual state reached.

Thanks Takashi for replying. I guess, I  should make use of return value from 
codec_read and retry if power state is not set properly! I'll make those 
changes and update again. And just wondering, how does hdmi_codec_prepare() and 
hdmi_codec_complete() gurantee while powering up and down the afg ?

Warm Regards,
Abhijeet

RE: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Kumar, Abhijeet]

> It's better, but doesn't guarantee that the node reached the given power 
> state.  codec_read assures that the verb is sent and the codec gives the 
> response.  But it means only the target state gets updated, and doesn't mean 
> that the actual state reached.

Thanks Takashi for replying. I guess, I  should make use of return value from 
codec_read and retry if power state is not set properly! I'll make those 
changes and update again. And just wondering, how does hdmi_codec_prepare() and 
hdmi_codec_complete() gurantee while powering up and down the afg ?

Warm Regards,
Abhijeet

Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Takashi Iwai]

On Fri, 12 Jan 2018 09:25:54 +0100,
 Kumar, Abhijeet  wrote:
> 
> 
> 
> On 1/12/2018 11:16 AM, Vinod Koul wrote:
> > On Thu, Jan 11, 2018 at 05:04:27PM +0530, abhijeet.ku...@intel.com wrote:
> >> From: Abhijeet Kumar 
> >>
> >> When we change the resolution of DP pannel or hot plug-unplug it while
> >> playing an audio clip,sometimes we observe a silent playback(no audio).
> > can you rephrase this please
> done please review v2!
> >> During no audio condition, we have noticed that the power state of the
> >> pin or the connector is D3. Optimzing the way we set the power could
> >> mitigate the issue.With this changes the verb is sent to set the power
> > space after .
> >
> >> state and response is received. Thus ensuring power state is set.
> > am not sure I fully understood the problem here
> 
> This appears to be an timing issue, while performing a stress test, we
> found out that sometimes either pin or converters are not powered
> up. Thus ensuring it that the power state is set correctly.
> 
> >
> >> Signed-off-by: Abhijeet Kumar 
> >> ---
> >>   sound/soc/codecs/hdac_hdmi.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/sound/soc/codecs/hdac_hdmi.c b/sound/soc/codecs/hdac_hdmi.c
> >> index f3b4f4dfae6a..e24caecf0a4f 100644
> >> --- a/sound/soc/codecs/hdac_hdmi.c
> >> +++ b/sound/soc/codecs/hdac_hdmi.c
> >> @@ -718,7 +718,7 @@ static void hdac_hdmi_set_power_state(struct 
> >> hdac_ext_device *edev,
> >>   {
> >>if (get_wcaps(>hdac, nid) & AC_WCAP_POWER) {
> >>if (!snd_hdac_check_power_state(>hdac, nid, pwr_state))
> >> -  snd_hdac_codec_write(>hdac, nid, 0,
> >> +  snd_hdac_codec_read(>hdac, nid, 0,
> > how does read help instead of write?
> 
> Indeed i'm making use of read instead of write to send the set command.
> 
> But unlike codec_write, codec_read send the verb synchronously. Maybe
> if you read the comment while powering up and down in
> hdmi_codec_prepare and hdmi_codec_complete you would understand
> better.
> 
> "codec_read is preferred over codec_write to set the power state.
> 
> This way verb is send to set the power state and response is
> received. So setting power state is ensured without using loop to read
> the state."

It's better, but doesn't guarantee that the node reached the given
power state.  codec_read assures that the verb is sent and the codec
gives the response.  But it means only the target state gets updated,
and doesn't mean that the actual state reached.


thanks,

Takashi

Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Takashi Iwai]

On Fri, 12 Jan 2018 09:25:54 +0100,
 Kumar, Abhijeet  wrote:
> 
> 
> 
> On 1/12/2018 11:16 AM, Vinod Koul wrote:
> > On Thu, Jan 11, 2018 at 05:04:27PM +0530, abhijeet.ku...@intel.com wrote:
> >> From: Abhijeet Kumar 
> >>
> >> When we change the resolution of DP pannel or hot plug-unplug it while
> >> playing an audio clip,sometimes we observe a silent playback(no audio).
> > can you rephrase this please
> done please review v2!
> >> During no audio condition, we have noticed that the power state of the
> >> pin or the connector is D3. Optimzing the way we set the power could
> >> mitigate the issue.With this changes the verb is sent to set the power
> > space after .
> >
> >> state and response is received. Thus ensuring power state is set.
> > am not sure I fully understood the problem here
> 
> This appears to be an timing issue, while performing a stress test, we
> found out that sometimes either pin or converters are not powered
> up. Thus ensuring it that the power state is set correctly.
> 
> >
> >> Signed-off-by: Abhijeet Kumar 
> >> ---
> >>   sound/soc/codecs/hdac_hdmi.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/sound/soc/codecs/hdac_hdmi.c b/sound/soc/codecs/hdac_hdmi.c
> >> index f3b4f4dfae6a..e24caecf0a4f 100644
> >> --- a/sound/soc/codecs/hdac_hdmi.c
> >> +++ b/sound/soc/codecs/hdac_hdmi.c
> >> @@ -718,7 +718,7 @@ static void hdac_hdmi_set_power_state(struct 
> >> hdac_ext_device *edev,
> >>   {
> >>if (get_wcaps(>hdac, nid) & AC_WCAP_POWER) {
> >>if (!snd_hdac_check_power_state(>hdac, nid, pwr_state))
> >> -  snd_hdac_codec_write(>hdac, nid, 0,
> >> +  snd_hdac_codec_read(>hdac, nid, 0,
> > how does read help instead of write?
> 
> Indeed i'm making use of read instead of write to send the set command.
> 
> But unlike codec_write, codec_read send the verb synchronously. Maybe
> if you read the comment while powering up and down in
> hdmi_codec_prepare and hdmi_codec_complete you would understand
> better.
> 
> "codec_read is preferred over codec_write to set the power state.
> 
> This way verb is send to set the power state and response is
> received. So setting power state is ensured without using loop to read
> the state."

It's better, but doesn't guarantee that the node reached the given
power state.  codec_read assures that the verb is sent and the codec
gives the response.  But it means only the target state gets updated,
and doesn't mean that the actual state reached.


thanks,

Takashi

RE: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Kumar, Abhijeet]

> can you rephrase this please
done please review v2! https://patchwork.kernel.org/patch/10159791/

> am not sure I fully understood the problem here
This appears to be an timing issue, while performing a stress test, we found 
out that sometimes either pin or converters are not powered up. Thus ensuring 
it that the power state is set correctly.

> how does read help instead of write?
Indeed i'm making use of read instead of write to send the set command. But 
unlike codec_write, codec_read send the verb synchronously. Maybe if you read 
the comment while powering up and down afg in hdmi_codec_prepare and 
hdmi_codec_complete you would understand better. 
"codec_read is preferred over codec_write to set the power state. This way verb 
is send to set the power state and response is received. So setting power state 
is ensured without using loop to read the state."

-Original Message-
From: Koul, Vinod 
Sent: Friday, January 12, 2018 11:17 AM
To: Kumar, Abhijeet <abhijeet.ku...@intel.com>
Cc: Liam Girdwood <lgirdw...@gmail.com>; Mark Brown <broo...@kernel.org>; 
Jaroslav Kysela <pe...@perex.cz>; Takashi Iwai <ti...@suse.com>; Kp, Jeeja 
<jeeja...@intel.com>; Prusty, Subhransu S <subhransu.s.pru...@intel.com>; 
Singh, Guneshwor O <guneshwor.o.si...@intel.com>; Tayal, SandeepX 
<sandeepx.ta...@intel.com>; alsa-de...@alsa-project.org; 
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget 
power state

On Thu, Jan 11, 2018 at 05:04:27PM +0530, abhijeet.ku...@intel.com wrote:
> From: Abhijeet Kumar <abhijeet.ku...@intel.com>
> 
> When we change the resolution of DP pannel or hot plug-unplug it while 
> playing an audio clip,sometimes we observe a silent playback(no audio).

can you rephrase this please

> During no audio condition, we have noticed that the power state of the 
> pin or the connector is D3. Optimzing the way we set the power could 
> mitigate the issue.With this changes the verb is sent to set the power

space after .

> state and response is received. Thus ensuring power state is set.

am not sure I fully understood the problem here

> 
> Signed-off-by: Abhijeet Kumar <abhijeet.ku...@intel.com>
> ---
>  sound/soc/codecs/hdac_hdmi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/hdac_hdmi.c 
> b/sound/soc/codecs/hdac_hdmi.c index f3b4f4dfae6a..e24caecf0a4f 100644
> --- a/sound/soc/codecs/hdac_hdmi.c
> +++ b/sound/soc/codecs/hdac_hdmi.c
> @@ -718,7 +718,7 @@ static void hdac_hdmi_set_power_state(struct 
> hdac_ext_device *edev,  {
>   if (get_wcaps(>hdac, nid) & AC_WCAP_POWER) {
>   if (!snd_hdac_check_power_state(>hdac, nid, pwr_state))
> - snd_hdac_codec_write(>hdac, nid, 0,
> + snd_hdac_codec_read(>hdac, nid, 0,

how does read help instead of write?

--
~Vinod

RE: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Kumar, Abhijeet]

> can you rephrase this please
done please review v2! https://patchwork.kernel.org/patch/10159791/

> am not sure I fully understood the problem here
This appears to be an timing issue, while performing a stress test, we found 
out that sometimes either pin or converters are not powered up. Thus ensuring 
it that the power state is set correctly.

> how does read help instead of write?
Indeed i'm making use of read instead of write to send the set command. But 
unlike codec_write, codec_read send the verb synchronously. Maybe if you read 
the comment while powering up and down afg in hdmi_codec_prepare and 
hdmi_codec_complete you would understand better. 
"codec_read is preferred over codec_write to set the power state. This way verb 
is send to set the power state and response is received. So setting power state 
is ensured without using loop to read the state."

-Original Message-
From: Koul, Vinod 
Sent: Friday, January 12, 2018 11:17 AM
To: Kumar, Abhijeet 
Cc: Liam Girdwood ; Mark Brown ; 
Jaroslav Kysela ; Takashi Iwai ; Kp, Jeeja 
; Prusty, Subhransu S ; 
Singh, Guneshwor O ; Tayal, SandeepX 
; alsa-de...@alsa-project.org; 
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget 
power state

On Thu, Jan 11, 2018 at 05:04:27PM +0530, abhijeet.ku...@intel.com wrote:
> From: Abhijeet Kumar 
> 
> When we change the resolution of DP pannel or hot plug-unplug it while 
> playing an audio clip,sometimes we observe a silent playback(no audio).

can you rephrase this please

> During no audio condition, we have noticed that the power state of the 
> pin or the connector is D3. Optimzing the way we set the power could 
> mitigate the issue.With this changes the verb is sent to set the power

space after .

> state and response is received. Thus ensuring power state is set.

am not sure I fully understood the problem here

> 
> Signed-off-by: Abhijeet Kumar 
> ---
>  sound/soc/codecs/hdac_hdmi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/hdac_hdmi.c 
> b/sound/soc/codecs/hdac_hdmi.c index f3b4f4dfae6a..e24caecf0a4f 100644
> --- a/sound/soc/codecs/hdac_hdmi.c
> +++ b/sound/soc/codecs/hdac_hdmi.c
> @@ -718,7 +718,7 @@ static void hdac_hdmi_set_power_state(struct 
> hdac_ext_device *edev,  {
>   if (get_wcaps(>hdac, nid) & AC_WCAP_POWER) {
>   if (!snd_hdac_check_power_state(>hdac, nid, pwr_state))
> - snd_hdac_codec_write(>hdac, nid, 0,
> + snd_hdac_codec_read(>hdac, nid, 0,

how does read help instead of write?

--
~Vinod

Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Vinod Koul]

On Thu, Jan 11, 2018 at 05:04:27PM +0530, abhijeet.ku...@intel.com wrote:
> From: Abhijeet Kumar 
> 
> When we change the resolution of DP pannel or hot plug-unplug it while
> playing an audio clip,sometimes we observe a silent playback(no audio).

can you rephrase this please

> During no audio condition, we have noticed that the power state of the
> pin or the connector is D3. Optimzing the way we set the power could
> mitigate the issue.With this changes the verb is sent to set the power

space after .

> state and response is received. Thus ensuring power state is set.

am not sure I fully understood the problem here

> 
> Signed-off-by: Abhijeet Kumar 
> ---
>  sound/soc/codecs/hdac_hdmi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/hdac_hdmi.c b/sound/soc/codecs/hdac_hdmi.c
> index f3b4f4dfae6a..e24caecf0a4f 100644
> --- a/sound/soc/codecs/hdac_hdmi.c
> +++ b/sound/soc/codecs/hdac_hdmi.c
> @@ -718,7 +718,7 @@ static void hdac_hdmi_set_power_state(struct 
> hdac_ext_device *edev,
>  {
>   if (get_wcaps(>hdac, nid) & AC_WCAP_POWER) {
>   if (!snd_hdac_check_power_state(>hdac, nid, pwr_state))
> - snd_hdac_codec_write(>hdac, nid, 0,
> + snd_hdac_codec_read(>hdac, nid, 0,

how does read help instead of write?

-- 
~Vinod

Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Vinod Koul]

On Thu, Jan 11, 2018 at 05:04:27PM +0530, abhijeet.ku...@intel.com wrote:
> From: Abhijeet Kumar 
> 
> When we change the resolution of DP pannel or hot plug-unplug it while
> playing an audio clip,sometimes we observe a silent playback(no audio).

can you rephrase this please

> During no audio condition, we have noticed that the power state of the
> pin or the connector is D3. Optimzing the way we set the power could
> mitigate the issue.With this changes the verb is sent to set the power

space after .

> state and response is received. Thus ensuring power state is set.

am not sure I fully understood the problem here

> 
> Signed-off-by: Abhijeet Kumar 
> ---
>  sound/soc/codecs/hdac_hdmi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/hdac_hdmi.c b/sound/soc/codecs/hdac_hdmi.c
> index f3b4f4dfae6a..e24caecf0a4f 100644
> --- a/sound/soc/codecs/hdac_hdmi.c
> +++ b/sound/soc/codecs/hdac_hdmi.c
> @@ -718,7 +718,7 @@ static void hdac_hdmi_set_power_state(struct 
> hdac_ext_device *edev,
>  {
>   if (get_wcaps(>hdac, nid) & AC_WCAP_POWER) {
>   if (!snd_hdac_check_power_state(>hdac, nid, pwr_state))
> - snd_hdac_codec_write(>hdac, nid, 0,
> + snd_hdac_codec_read(>hdac, nid, 0,

how does read help instead of write?

-- 
~Vinod