• Takashi Iwai's avatar
    ALSA: hda: Fix too short HDMI/DP chmap reporting · c2432466
    Takashi Iwai authored
    We got a regression report about the HD-audio HDMI chmap, where some
    surround channels are reported as UNKNOWN.  The git bisection pointed
    the culprit at the commit 9b3dc8aa ("ALSA: hda - Register chmap
    obj as priv data instead of codec").  The story behind scene is like
    this:
    
    - While moving the code out of the legacy HDA to the HDA common place,
      the patch modifies the code to obtain the chmap array indirectly in
      a byte array, and it expands it to kctl value array.
    - At the latter operation, the size of the array is wrongly passed by
      sizeof() to the pointer.
    - It can be 4 on 32bit arch, thus too short for 6+ channels.
      (And that's the reason why it didn't hit other persons; it's 8 on
      64bit arch, thus it's usually enough.)
    
    The code was further changed meanwhile, but the problem persisted.
    Let's fix it by correctly evaluating the array size.
    
    Fixes: 9b3dc8aa ("ALSA: hda - Register chmap obj as priv data instead of codec")
    Reported-by: default avatarVDR User <user.vdr@gmail.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    c2432466
hdmi_chmap.c 24.2 KB