> -----Original Message----- > From: Ville Syrjälä [mailto:ville.syrjala@xxxxxxxxxxxxxxx] > Sent: Tuesday, February 18, 2014 10:23 PM > To: Lin, Mengdong > Cc: Daniel Vetter; Takashi Iwai; alsa-devel@xxxxxxxxxxxxxxxx; Barnes, Jesse; > Zanoni, Paulo R; dri-devel; intel-gfx@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: Need your advice: Add a new communication > inteface between HD-Audio and Gfx drivers for hotplug notification/ELD > update > > On Tue, Feb 18, 2014 at 01:58:22PM +0000, Lin, Mengdong wrote: > > Sorry to pick up this thread after a long time. > > > > > -----Original Message----- > > > From: daniel.vetter@xxxxxxxx [mailto:daniel.vetter@xxxxxxxx] On > > > Behalf Of Daniel Vetter > > > Sent: Thursday, January 23, 2014 4:27 PM > > > To: Takashi Iwai > > > > > On Thu, Jan 23, 2014 at 8:57 AM, Takashi Iwai <tiwai@xxxxxxx> wrote: > > > >> Thanks for clarification! > > > >> Maybe we can add output info (eg. display port number) to the eld > > > >> entries > > > under /proc/asound/cardx. Is it okay? > > > > > > > > It's possible, but the proc file is just a help. It can't be the API. > > > > For accessing the information, we'll need some new API, or let > > > > inform via sysfs of the new device. > > > > > > Links in sysfs sound like the best approach. drm already has nodes > > > for each connector, so on the gfx side there's a natural endpoint > already. > > > sysfs links also avoids any naming issues from the start, e.g. the > > > above DP connector id might lead to clashes with multiple cards. > > > > Hi Daniel, > > > > Is there a 1:1 mapping between these connector nodes and ports of Gfx > display engine? > > Eg. For Haswell Ultrabook, under > > /sys/devices/pci0000:00/0000:00:02.0/drm/card0/ > > There are four connector nodes, > > card0-DP-1 -> DDI port B > > card0-eDP-1/ -> DDI port A > > card0-HDMI-A-1/ -> DDI Port C > > card0-HDMI-A-2/ -> Which DDI port ? Haswell-ULT does not > support port D, and I think port E is for VGA. > > There's no fixed mapping with the port and the connector name. The > number in the connector name is basically just a running number per > connector type. However I do believe we do register the connectors in the > order of the ports more or less always, so you can > *sometimes* deduce the port name from the connector. > > I suppose in this example HDMI-A-1 is port B, HDMI-A-2 is port C, and > DP-1 can be either port B or port C. DP++ is the reason why we have > overlapping DP and HDMI connectors for the same port. Thanks for clarification, Ville! Does Haswell support DP++ on port B/C/D? And will the name of these connector node change after system boot, e.g. after S3/S4 cycles or hot-plug? As long as the connector name is constant, it can help to find out the screen status no matter the port works in HDMI or DP mode. There is 1:1 mapping between audio output pins and DDI ports. And the new ALSA PCM 'screen' control for a pin can reflect the connector name in right mode. E.g. for pin/port B, it can return HDMI-A-1 or DP-1 depending on what kind of monitor is connected. Thanks Mengdong > > > > Hi Takashi, > > > > To make user space figure out which audio output is connected to which > screen (connector), maybe we can define a new ALSA control for each > HDMI/DP PCM device: > > e.g. numid=x,iface=PCM,name='Screen',device=3 > > Reading the control will return the name of the DRM connector nodes > like ' card0-DP-1'. The audio driver can get the connector name from the > gfx driver. > > > > For DP1.2 Multi-stream transport, it's not supported by i915 and HD-A > driver now. But probably there will be sub-nodes for the DP connector > node in the future and an index in their name can be used distinguish > monitors connected to the same DP port, like card0-DP-1.1, card0-DP-1.2, > card0-DP-1.3 ... These names can be used by the above ALSA PCM 'Screen' > control, so we can still know which audio output is to which monitor. > > > > Thanks > > Mengdong > > > > _______________________________________________ > > Intel-gfx mailing list > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- > Ville Syrjälä > Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
