• Ville Syrjälä's avatar
    drm/i915: Get HDR DPCD refresh timeout from VBT · fe82b93f
    Ville Syrjälä authored
    Grab the HDR DPCD refresh timeout (time we need to wait after
    writing the sourc OUI before the HDR DPCD registers are ready)
    from the VBT.
    
    Windows doesn't even seem to have any default value for this,
    which is perhaps a bit weird since the VBT value is documented
    as TGL+ and I thought the HDR backlight stuff might already be
    used on earlier platforms. To play it safe I left the old
    hardcoded 30ms default in place. Digging through some internal
    stuff that seems to have been a number given by the vendor for
    one particularly slow TCON. Although I did see 50ms mentioned
    somewhere as well.
    
    Let's also include the value in the debug print to ease
    debugging, and toss in the customary connector id+name as well.
    
    The TGL Thinkpad T14 I have sets this to 0 btw. So the delay
    is now gone on this machine:
     [CONNECTOR:308:eDP-1] Detected Intel HDR backlight interface version 1
     [CONNECTOR:308:eDP-1] Using Intel proprietary eDP backlight controls
     [CONNECTOR:308:eDP-1] SDR backlight is controlled through PWM
     [CONNECTOR:308:eDP-1] Using native PCH PWM for backlight control (controller=0)
     [CONNECTOR:308:eDP-1] Using AUX HDR interface for backlight control (range 0..496)
     [CONNECTOR:308:eDP-1] Performing OUI wait (0 ms)
    
    Cc: Lyude Paul <lyude@redhat.com>
    Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
    Link: https://patchwork.freedesktop.org/patch/msgid/20230220164718.23117-1-ville.syrjala@linux.intel.comReviewed-by: default avatarJouni Högander <jouni.hogander@intel.com>
    fe82b93f
intel_dp.c 160 KB