displayengine/libs/core/display_hdmi.cpp

/*
* Copyright (c) 2014, The Linux Foundation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted
* provided that the following conditions are met:
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*
* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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#include <utils/constants.h>
#include <utils/debug.h>

#include "display_hdmi.h"

#define __CLASS__ "DisplayHDMI"

namespace sde {

DisplayHDMI::DisplayHDMI(DisplayEventHandler *event_handler, HWInterface *hw_intf,
                         CompManager *comp_manager)
  : DisplayBase(kHDMI, event_handler, kDeviceHDMI, hw_intf, comp_manager) {
}

int DisplayHDMI::GetBestConfig() {
  uint32_t best_config_mode = 0;
  HWDisplayAttributes *best = &display_attributes_[0];
  if (num_modes_ == 1) {
    return best_config_mode;
  }

  // From the available configs, select the best
  // Ex: 1920x1080@60Hz is better than 1920x1080@30 and 1920x1080@30 is better than 1280x720@60
  for (uint32_t index = 1; index < num_modes_; index++) {
    HWDisplayAttributes *current = &display_attributes_[index];
    // compare the two modes: in the order of Resolution followed by refreshrate
    if (current->y_pixels > best->y_pixels) {
      best_config_mode = index;
    } else if (current->y_pixels == best->y_pixels) {
      if (current->x_pixels > best->x_pixels) {
        best_config_mode = index;
      } else if (current->x_pixels == best->x_pixels) {
        if (current->vsync_period_ns < best->vsync_period_ns) {
          best_config_mode = index;
        }
      }
    }
    if (best_config_mode == index) {
      best = &display_attributes_[index];
    }
  }

  return best_config_mode;
}

}  // namespace sde