-----Original Message----- From: David Henningsson [mailto:david.henningsson@canonical.com] Sent: Thursday, October 22, 2015 4:53 PM
[snip]
I'll try to explain my suggestion (which I believe Takashi's buying too) one more time then:
First, when a monitor is plugged in, we need to dynamically assign this monitor to five PCM devices. I believe this scheme will be best:
For a monitor at pin nid 0x05, dev index 0, it will prefer PCM 3. For a monitor at pin nid 0x06, dev index 0, it will prefer PCM 7. For a monitor at pin nid 0x07, dev index 0, it will prefer PCM 8. For a monitor at dev index 1 (any pin), it will prefer PCM 9. For a monitor at dev index 2 (any pin), it will prefer PCM 10.
For monitors at dev indices > 2 (can that happen?), or if the PCM is already assigned to something else, try PCMs in this order: 9, 10, 3, 7, 8. (Subject to discussion perhaps, I don't think the order matters too much, because conflicts will be rare in practice.)
Hi David,
Would you please clarify why PA needs such a fixed binding between PCM 3,7, 8 and pin 0x05,6,7?
And how will PA handle PCM 9,10 in a different way? They are not bound to pins, and even not able to dev indexes. In practice, a platform will usually support either a DP port or a HDMI port from the Intel integrated GPU for cost consideration. But theoretically i915 can use same device index on two different pins to connect monitors, e.g. pin 0x05, dev index 2 for one monitor and pin 0x06, dev index 2 for the other.
On Intel platforms, the max dev indices is 2. Not sure about Nvidia and AMD.
Thanks Mengdong