drm/i915: Improve DP downstream HPD handling
authorVille Syrjälä <ville.syrjala@linux.intel.com>
Fri, 27 Oct 2017 09:45:23 +0000 (12:45 +0300)
committerVille Syrjälä <ville.syrjala@linux.intel.com>
Fri, 27 Oct 2017 19:14:46 +0000 (22:14 +0300)
commit857c416e58dc306b15b7919117b6225544662bfa
treed1f38afd5547ecf7239a5ab3d82dcf67fb041aee
parent5161d058dff4d53c78a046350d64beff54e9a9f7
drm/i915: Improve DP downstream HPD handling

DP dongles may signal downstream HPD via short HPD pulses. Setting the
sink to DPMS off apparently kills the downstream HPD (at least on my
DP->VGA dongle), so skip the DPMS off for such dongles when we turn
off the port.

v2: Deal with DDI as well by moving the check into
    intel_dp_sink_dpms() (Dhinakaran)

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Pablo <pablodebiase@nanalysis.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103472
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99114
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171027094523.9317-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
drivers/gpu/drm/i915/intel_dp.c