Hi Takashi,
On 11/09/2015 11:15 PM, Takashi Iwai wrote:
On Mon, 09 Nov 2015 16:00:01 +0100,
Yang, Libin wrote:
Hi Takashi,
-----Original Message-----
From: Takashi Iwai [mailto:tiwai@xxxxxxx]
Sent: Monday, November 09, 2015 3:59 PM
To: Libin Yang
Cc: alsa-devel@xxxxxxxxxxxxxxxx; mengdong.lin@xxxxxxxxxxxxxxx; Yang,
Libin
Subject: Re: [RFC PATCH 0/2] ALSA: hda - DP MST audio for
Jack support
On Wed, 04 Nov 2015 07:23:14 +0100,
Libin Yang wrote:
On 11/04/2015 12:49 AM, Takashi Iwai wrote:
On Tue, 03 Nov 2015 09:42:54 +0100,
libin.yang@xxxxxxxxxxxxxxx wrote:
From: Libin Yang <libin.yang@xxxxxxxxxxxxxxx>
This is the patch set for Jack support for DP MST audio
Libin Yang (2):
ALSA: hda - jack support DP MST audio
ALSA: hda - hdmi audio add dynamically jack binding to pin
I'm somehow confused by this patch series.
Is the unsolicited event handling itself changed for MST? I mean, you
cannot know which MST dev# is given beforehand, while you seem
trying
to assign such a number to the jack object.
Oh, sorry I forgot to mention that we only operate on device entry 0
so far in the code. It's misleading.
These patches don't operate on MST audio. The full MST audio driver
support will be implemented in the later patches. The patches help to
prepare supporting MST audio.
The purpose of the patches is try to dynamically attach the Jack.
Well, only judging from the quick glance, I don't buy this strategy,
sorry. Currently for HDMI/DP, the jack is for PCM, not for pin.
Namely, user-space watches the jack notification to judge whether the
corresponding PCM is available or not. You're trying to change this
scheme completely.
The patch is to make sure the jack is bound to PCM statically.
This patch is needed because in old code, it will create jack with:
for (pin_idx = 0; pin_idx < spec->num_pins; pin_idx++) {
...
err = generic_hdmi_build_jack(codec, pin_idx);
...
}
Which means the jack is created based on pin number and pin_idx.
As a pin is bound statically to the PCM, the jack is statically bound to PCM.
OK, so far, so good.
Now we are using the dynamic pcm bound. If we use the old code to
create the jack, the jack will be bound to pin. So we need the patch,
which will use the new code:
for (pcm_idx = 0; pcm_idx < spec-> pcms_used; pcm_idx++) {
...
err = generic_hdmi_build_jack(codec, pcm_idx);
...
}
which makes sure that the jack is bound to PCM (jack[0] is bound
to pcm[0], jack[1] is bound to pcm[1] and so on).
If there is no monitor, no pin is bound to the PCM.
So no pin is bound to the Jack. When there is a monitor connected,
the pin is bound to a proper PCM. So we should bind the PCM's jack
to the pin.
For example, jack0 is bound to the PCM 3 (the first jack is bound
to the first PCM statically). When a monitor is connected to pin 5,
PCM 3 will be assigned to the pin. We need bind jack 0 to pin 5.
When monitor is disconnected, we must unbind the jack 0 from pin 5.
These operation are done in function
snd_hda_jack_bind/ snd_hda_jack_unbind.
Then we shouldn't use the hda_jack.c code at all for HDMI/DP.
For HDMI/DP with the dynamic PCM binding, the only state to check is
its PCM assignment. It doesn't have to issue the jack state check via
HDA verb at all. This should make things a lot easier.
I'm now porting the jack supporting for MST audio. The code on
hdmi-jack branch will create jack differently based codec_has_acomp()
condition. Does this mean MST Jack binding will handle both situation?
My idea is:
1. Add struct snd_jack *jack[] member in hdmi_spec.
2. Create the jack based on PCM
3. Assign spec->jack[i] to per_pin->acomp_jack when pin is connected.
This should be OK for codec_has_acomp sitation. But what about the
other situation? The other situation still uses the hda_jack_tbl and
etc. So we still need handle hda jack if we want to reuse the current
code.
Best Regards,
Libin
Takashi
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