Hi Takashi,
-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Friday, October 16, 2015 5:01 PM To: Yang, Libin Cc: Raymond Yau; ALSA Development Mailing List; airlied@linux.ie; Lin, Mengdong; Girdwood, Liam R; tanuk@iki.fi; David Henningsson Subject: Re: [alsa-devel] DP1.2 MST audio support discussion
On Fri, 16 Oct 2015 10:51:30 +0200, Yang, Libin wrote:
Hi Takashi,
-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Friday, October 16, 2015 2:38 PM To: Raymond Yau Cc: Yang, Libin; ALSA Development Mailing List; airlied@linux.ie; Lin, Mengdong; Girdwood, Liam R; tanuk@iki.fi; David Henningsson Subject: Re: [alsa-devel] DP1.2 MST audio support discussion
On Fri, 16 Oct 2015 02:32:50 +0200, Raymond Yau wrote:
Do it mean that only one DP MST port and no HDMI port on
the
same
graphic
card ?
No.
If there is only one HDMI and one Display Port, this mean that
there
are
two pin complexes
Yes, and the mapping doesn't change in this case as before.
How about the name of jack detection kctl of three Display Port
monitors
which are created on the same pin complex but different
dev_index ?
It's one of the models we've considered. Basically the number of devices can be up to 64 (or such) per pin. For Intel case, due to the limitation of converters, it's up to 3. For other GPUs that may drive more simultaneous outputs, the number increases in square. If a
GPU
may handle 16 outputs, it'll be 256 entries.
Although the 256 entries are certainly manageable as kctl, whether this is the best representation for user-space is a question.
This is what I concern. Each device entry should have one tag for unsol event. This means each device entry will create a jack?
Yes, and essentially each entry corresponds to a PCM, so we'll end up with 256 PCM (sub)streams :) This doesn't scale.
So, thinking of this issue again, I'm convinced now that static PCM entries with extra dynamic PCM slots as David suggested would work more safely. The number of dynamic PCMs can be either a fixed number per driver type, a constant, or variable via module option.
Yes, we will use static PCM allocation and dynamic PCM attachment. :)
For the Jack, I think I need do some investigation on the HW whether I can use dynamic attachment or not.
Takashi