• Benjamin Herrenschmidt's avatar
    [PATCH] ppc64: very basic desktop g5 sound support · 7bbd8277
    Benjamin Herrenschmidt authored
    This patch hacks the current PowerMac Alsa driver to add some basic support
    of analog sound output to some desktop G5s.  It has severe limitations
    though:
    
     - Only 44100Khz 16 bits
     - Only work on G5 models using a TAS3004 analog code, that is early
       single CPU desktops and all dual CPU desktops at this date, but none
       of the more recent ones like iMac G5.
     - It does analog only, no digital/SPDIF support at all, no native
       AC3 support
    
    Better support would require a complete rewrite of the driver (which I am
    working on, but don't hold your breath), to properly support the diversity
    of apple sound HW setup, including dual codecs, several i2s busses, all the
    new codecs used in the new machines, proper clock switching with digital,
    etc etc etc...
    
    This patch applies on top of the other PowerMac sound patches I posted in
    the past couple of days (new powerbook support and sleep fixes).  
    
    Note: This is a FAQ entry for PowerMac sound support with TI codecs: They
    have a feature called "DRC" which is automatically enabled for the internal
    speaker (at least when auto mute control is enabled) which will cause your
    sound to fade out to nothing after half a second of playback if you don't
    set a proper "DRC Range" in the mixer.  So if you have a problem like that,
    check alsamixer and raise your DRC Range to something reasonable.
    
    Note2: This patch will also add auto-mute of the speaker when line-out jack
    is used on some earlier desktop G4s (and on the G5) in addition to the
    headphone jack.  If that behaviour isn't what you want, just disable
    auto-muting and use the manual mute controls in alsamixer.
    Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    7bbd8277
keylargo.h 10.3 KB