Load and apply a vcgt table from an ICC file to the internal display

ui/ozone/platform/drm/gpu/drm_device.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/ozone/platform/drm/gpu/drm_device.h"
 
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <unistd.h>
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/stl_util.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "third_party/skia/include/core/SkImageInfo.h"
+#include "ui/display/types/gamma_ramp_rgb_entry.h"
 #include "ui/ozone/platform/drm/gpu/drm_util.h"
 #include "ui/ozone/platform/drm/gpu/hardware_display_plane_manager_legacy.h"
 
 #if defined(USE_DRM_ATOMIC)
 #include "ui/ozone/platform/drm/gpu/hardware_display_plane_manager_atomic.h"
 #endif
 
 namespace ui {
 
 namespace {
@@ skipping 466 matching lines @@
 bool DrmDevice::SetMaster() {
   DCHECK(file_.IsValid());
   return (drmSetMaster(file_.GetPlatformFile()) == 0);
 }
 
 bool DrmDevice::DropMaster() {
   DCHECK(file_.IsValid());
   return (drmDropMaster(file_.GetPlatformFile()) == 0);
 }
 
+bool DrmDevice::SetGammaRamp(uint32_t crtc_id,
+                             const std::vector<GammaRampRGBEntry>& lut) {
+  ScopedDrmCrtcPtr crtc = GetCrtc(crtc_id);
+
+  // TODO(robert.bradford) resample the incoming ramp to match what the kernel
+  // expects.
+  if (static_cast<size_t>(crtc->gamma_size) != lut.size()) {
+    LOG(ERROR) << "Gamma table size mismatch: supplied " << lut.size()
+               << " expected " << crtc->gamma_size;
+  }
+
+  std::vector<uint16_t> r, g, b;
+  r.resize(lut.size());

[dcheng, 2015/04/30 20:40:24]

Nit: reserve instead of resize.

+  g.resize(lut.size());
+  b.resize(lut.size());
+
+  for (size_t i = 0; i < lut.size(); ++i) {
+    r[i] = lut[i].r;
+    g[i] = lut[i].g;
+    b[i] = lut[i].b;
+  }
+
+  DCHECK(file_.IsValid());
+  TRACE_EVENT0("drm", "DrmDevice::SetGamma");
+  return (drmModeCrtcSetGamma(file_.GetPlatformFile(), crtc_id, r.size(), &r[0],
+                              &g[0], &b[0]) == 0);
+}
+
 }  // namespace ui