On Wed, 16 Mar 2016 08:48:58 +0100, Yang, Libin wrote:
Hi Takashi,
-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Wednesday, March 16, 2016 3:35 PM To: libin.yang@linux.intel.com Cc: alsa-devel@alsa-project.org; Yang, Libin; Lin, Mengdong Subject: Re: [alsa-devel] [PATCH] ALSA: hda - codec add DP MST support for connection list
On Wed, 16 Mar 2016 02:47:31 +0100, libin.yang@linux.intel.com wrote:
From: Libin Yang libin.yang@linux.intel.com
This patches adds the support of connection list for DP MST. With this, hdmi driver in DP MST mode can easily reuse the connection list mechanism.
Signed-off-by: Libin Yang libin.yang@linux.intel.com
The merge window was already opened, so it's too late for this kind of change for 4.6, in anyway.
That's OK. We can wait for later version. What do you think put this patch and my later patches for MST in the topic branch, such as hdmi-jack brach like before. Later patches for MST needs gfx driver support and our gfx driver is not ready for it.
But, the fundamental question: why do we need to manage the cached list of the widget connection with a device index? In other words, if you have a different device index, does the widget connection itself also change?
Based on my test, it should be the same. But from the spec, it says:
7.3.3.42 Device Select For Digital Display Pin Widget that is multi stream capable, the Device Select control determines which Device Entry is currently selected and accessible by the Pin Widget verbs which are controlling the sink device operations. This control verb is only required if it is a Digital Display Pin Widget and multi stream capable. The index is in relation to the Device List associated with the widget. The index is a zero-based offset into the Device List. Once the Device Entry is selected by the Set index, all subsequent Pin Widget verbs controlling the sink device operations will be directed to the selected Device Entry, until the Device Select verb get updated with a new value. These Pin Widget verbs include: Connection Select Get Connection List Entry Amplifier Gain/Mute Power State Pin Widget Control ELD Data DIP-Size DIP-Index DIP-Data DIP-XmitCtrl Content Protection Control ASP Channel Mapping
So my understand is this may be changed.
But the pin widget is the terminal. So, if you have a device index to choose a device there, the widget connection list itself doesn't change. Or am I missing anything?
Takashi