• Takashi Iwai's avatar
    ALSA: hda: Skip controller resume if not needed · c4c8dd6e
    Takashi Iwai authored
    The HD-audio controller does system-suspend and resume operations by
    directly calling its helpers __azx_runtime_suspend() and
    __azx_runtime_resume().  However, in general, we don't have to resume
    always the device fully at the system resume; typically, if a device
    has been runtime-suspended, we can leave it to runtime resume.
    
    Usually for achieving this, the driver would call
    pm_runtime_force_suspend() and pm_runtime_force_resume() pairs in the
    system suspend and resume ops.  Unfortunately, this doesn't work for
    the resume path in our case.  For handling the jack detection at the
    system resume, a child codec device may need the (literally) forcibly
    resume even if it's been runtime-suspended, and for that, the
    controller device must be also resumed even if it's been suspended.
    
    This patch is an attempt to improve the situation.  It replaces the
    direct __azx_runtime_suspend()/_resume() calls with with
    pm_runtime_force_suspend() and pm_runtime_force_resume() with a slight
    trick as we've done for the codec side.  More exactly:
    
    - azx_has_pm_runtime() check is dropped from azx_runtime_suspend() and
      azx_runtime_resume(), so that it can be properly executed from the
      system-suspend/resume path
    
    - The WAKEEN handling depends on the card's power state now; it's set
      and cleared only for the runtime-suspend
    
    - azx_resume() checks whether any codec may need the forcible resume
      beforehand.  If the forcible resume is required, it does temporary
      PM refcount up/down for actually triggering the runtime resume.
    
    - A new helper function, hda_codec_need_resume(), is introduced for
      checking whether the codec needs a forcible runtime-resume, and the
      existing code is rewritten with that.
    
    BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=207043
    Link: https://lore.kernel.org/r/20200413082034.25166-6-tiwai@suse.deSigned-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    c4c8dd6e
hda_codec.h 17 KB