[Intel-gfx] [PATCH 0/2] Optimization on intel HDMI detect and get_modes

[Ramalingam C]

On slow HDMI hotplug out, because of the physical interface design,
DDC remains active for short duration even when HPD live status is
indicating the disconnect state. Because of this on VLV and HSW,
slow hotplug out events are not captured.

Hence this change uses the HPD pins live status to identify the
HDMI connector status.

Multiple forced detect and read modes calls come from
user space for different connectors, which can be handled
with connector status and previous detect event's cached EDID.
With this approach for hot pluggable displays, EDID retrieval
is required only when there is a real hot-plug events.

This change also includes:
1. A logic to optimize those multiple calls, by re-using
   cached data from previous detect and get_mode calls.
2. Store HDMI EDID, and re-use it in read modes.
3. Read live status reg to suppress spurious interrupts

These two changes will optimize the access to the DDC and also the
CPU cycles burned by intel_hdmi_detect and intel_hdmi_get_modes.

Ramalingam C (1):
  drm/i915: HDMI detection based on HPD pin live status

Shashank Sharma (1):
  drm/i915: Optimize EDID retrival on detect and get_modes

 drivers/gpu/drm/i915/intel_drv.h  |   12 +++
 drivers/gpu/drm/i915/intel_hdmi.c |  149 ++++++++++++++++++++++++++++++++-----
 2 files changed, 144 insertions(+), 17 deletions(-)

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1.7.9.5