From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: Need your advice: Add a new communication inteface between HD-Audio and Gfx drivers for hotplug notification/ELD update Date: Tue, 18 Feb 2014 16:22:32 +0200 Message-ID: <20140218142232.GS3852@intel.com> References: <20140122141821.GI9772@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org To: "Lin, Mengdong" Cc: "alsa-devel@alsa-project.org" , "Zanoni, Paulo R" , Takashi Iwai , "intel-gfx@lists.freedesktop.org" , dri-devel , "Barnes, Jesse" List-Id: intel-gfx@lists.freedesktop.org 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@ffwll.ch [mailto:daniel.vetter@ffwll.ch] 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 wrote: > > >> Thanks for clarification! > > >> Maybe we can add output info (eg. display port number) to the eld en= tries > > 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 abov= e 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 dis= play 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. > = > Hi Takashi, > = > To make user space figure out which audio output is connected to which sc= reen (connector), maybe we can define a new ALSA control for each HDMI/DP P= CM device: > e.g. numid=3Dx,iface=3DPCM,name=3D'Screen',device=3D3 > 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 dri= ver. > = > For DP1.2 Multi-stream transport, it's not supported by i915 and HD-A dri= ver 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 conn= ected 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@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- = Ville Syrj=E4l=E4 Intel OTC