At Fri, 23 Feb 2007 10:40:20 -0800, John Utz wrote: > > -----Original Message----- > From: Takashi Iwai [mailto:tiwai@xxxxxxx] > Sent: Fri 2/23/2007 7:14 AM > To: John Utz > Cc: alsa-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: doesn anybody actually ever assign to > snd_ac97.indep_surround? > > * The basic idea behind this implementation is that you set up the > * surround setting dynamically. There are two switches to play > * important roles that are created usually: > * > * 1. Surround Jack Mode > * enum: Shared / Independent > * 2. Channel Mode > * enum: 2ch / 4ch / 6ch > * > * When "Shared" is selected, the ac97 patch should set up the codec chip > * for the bidirectional pins. Inputs are turned to be surround outputs > * according to the the current status of channel mode (2, 4, 6ch). > * OTOH, when "Independent" is selected, it means that the board has > * separate surround jacks, so the inputs are always inputs. > * You should have update_jacks callback to update the jack status > * appropriately. This callback is called when the above mixer switches > * are changed. In the update_jacks callback, you can use helper > * function is_shared_surrout() and is_shared_clfeout() that tell you > * whether the line-in and mic-in jacks should be handled as output or > * not. > > this is an incredibly crucial point that motivated my mail in the first place! > > these helper functions are wrappers around a check to ac97->indep_surround. > > *who* fills this item out properly?? driver or user? The "Surround Jack Mode" mixer elements sets ac97->indep_surround on/off. > based on looking at ac97_patch.c::ac97_enum_text_info() it looks like the *driver* > expects the *user* to tell the driver how the board is configured. > > is my understanding correct? Yes, this information cannot be obtained from the hardware. There is no probe function. So, user (or the system admin) must set this properly. Takashi ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
