ozone-gbm: Workaround flip not able to change stride bug

gistfile1.txt

diff --git a/ui/ozone/platform/dri/buffer_data.cc b/ui/ozone/platform/dri/buffer_data.cc
index a2ea1b3..3462fd0 100644
--- a/ui/ozone/platform/dri/buffer_data.cc
+++ b/ui/ozone/platform/dri/buffer_data.cc
@@ -20,6 +20,7 @@ const uint8_t kPixelDepth = 32;
 BufferData::BufferData(DriWrapper* dri, gbm_bo* buffer)
     : dri_(dri),
       handle_(gbm_bo_get_handle(buffer).u32),
+      stride_(gbm_bo_get_stride(buffer)),
       framebuffer_(0) {
   // Register the buffer with the controller. This will allow us to scan out the
   // buffer once we're done drawing into it. If we can't register the buffer
diff --git a/ui/ozone/platform/dri/buffer_data.h b/ui/ozone/platform/dri/buffer_data.h
index 2f3422d..0578d3c 100644
--- a/ui/ozone/platform/dri/buffer_data.h
+++ b/ui/ozone/platform/dri/buffer_data.h
@@ -32,6 +32,7 @@ class BufferData {
 
   uint32_t framebuffer() const { return framebuffer_; }
   uint32_t handle() const { return handle_; }
+  uint32_t stride() const { return stride_; }
 
  private:
   BufferData(DriWrapper* dri, gbm_bo* buffer);
@@ -41,6 +42,8 @@ class BufferData {
 
   uint32_t handle_;
 
+  uint32_t stride_;
+
   // ID provided by the controller when the buffer is registered. This ID is
   // used when scanning out the buffer.
   uint32_t framebuffer_;
diff --git a/ui/ozone/platform/dri/dri_surface.cc b/ui/ozone/platform/dri/dri_surface.cc
index e0813b6..ed4a720 100644
--- a/ui/ozone/platform/dri/dri_surface.cc
+++ b/ui/ozone/platform/dri/dri_surface.cc
@@ -54,6 +54,11 @@ uint32_t DriSurface::GetHandle() const {
   return backbuffer()->handle();
 }
 
+uint32_t DriSurface::GetStride() const {
+  CHECK(backbuffer());
+  return backbuffer()->stride();
+}
+
 // This call is made after the hardware just started displaying our back buffer.
 // We need to update our pointer reference and synchronize the two buffers.
 void DriSurface::SwapBuffers() {
diff --git a/ui/ozone/platform/dri/dri_surface.h b/ui/ozone/platform/dri/dri_surface.h
index 9aa59b7..3749394 100644
--- a/ui/ozone/platform/dri/dri_surface.h
+++ b/ui/ozone/platform/dri/dri_surface.h
@@ -34,6 +34,7 @@ class DriSurface : public ScanoutSurface {
   virtual uint32_t GetHandle() const OVERRIDE;
   virtual void SwapBuffers() OVERRIDE;
   virtual gfx::Size Size() const OVERRIDE;
+  virtual uint32_t GetStride() const OVERRIDE;
 
  private:
   DriBuffer* frontbuffer() const { return bitmaps_[front_buffer_].get(); }
diff --git a/ui/ozone/platform/dri/gbm_surface.cc b/ui/ozone/platform/dri/gbm_surface.cc
index 99f0ae7..0aefa75 100644
--- a/ui/ozone/platform/dri/gbm_surface.cc
+++ b/ui/ozone/platform/dri/gbm_surface.cc
@@ -81,6 +81,16 @@ gfx::Size GbmSurface::Size() const {
   return size_;
 }
 
+uint32_t GbmSurface::GetStride() const {
+  if (!buffers_[front_buffer_ ^ 1])
+    return dumb_buffer_->stride();
+
+  BufferData* data = BufferData::GetData(buffers_[front_buffer_ ^ 1]);
+  CHECK(data);
+
+  return data->stride();
+}
+
 void GbmSurface::SwapBuffers() {
   // If there was a frontbuffer, is no longer active. Release it back to GBM.
   if (buffers_[front_buffer_])
diff --git a/ui/ozone/platform/dri/gbm_surface.h b/ui/ozone/platform/dri/gbm_surface.h
index 8a33ab5..ccf3ebb 100644
--- a/ui/ozone/platform/dri/gbm_surface.h
+++ b/ui/ozone/platform/dri/gbm_surface.h
@@ -33,6 +33,7 @@ class GbmSurface : public ScanoutSurface {
   virtual uint32_t GetHandle() const OVERRIDE;
   virtual gfx::Size Size() const OVERRIDE;
   virtual void SwapBuffers() OVERRIDE;
+  virtual uint32_t GetStride() const OVERRIDE;
 
   // Before scheduling the backbuffer to be scanned out we need to "lock" it.
   // When we lock it, GBM will give a pointer to a buffer representing the
diff --git a/ui/ozone/platform/dri/hardware_display_controller.cc b/ui/ozone/platform/dri/hardware_display_controller.cc
index 9e79118..e71a4d7 100644
--- a/ui/ozone/platform/dri/hardware_display_controller.cc
+++ b/ui/ozone/platform/dri/hardware_display_controller.cc
@@ -114,13 +114,23 @@ void HardwareDisplayController::Disable() {
 
 bool HardwareDisplayController::SchedulePageFlip() {
   CHECK(surface_);
-  if (!is_disabled_ && !drm_->PageFlip(crtc_id_,
-                                       surface_->GetFramebufferId(),
-                                       this)) {
+  if (is_disabled_)
+    return true;
+
+  if (surface_->GetStride() != current_stride_ &&
+      !drm_->SetCrtc(crtc_id_, surface_->GetFramebufferId(),
+                     &connector_id_, &mode_)) {
+    LOG(ERROR) << "Cannot mode set: " << strerror(errno);
+    return false;
+  }
+
+  if (!drm_->PageFlip(crtc_id_, surface_->GetFramebufferId(), this)) {
     LOG(ERROR) << "Cannot page flip: " << strerror(errno);
     return false;
   }
 
+  current_stride_ = surface_->GetStride();
+
   return true;
 }
 
diff --git a/ui/ozone/platform/dri/hardware_display_controller.h b/ui/ozone/platform/dri/hardware_display_controller.h
index 472dbd6..fb9cd8f 100644
--- a/ui/ozone/platform/dri/hardware_display_controller.h
+++ b/ui/ozone/platform/dri/hardware_display_controller.h
@@ -173,6 +173,8 @@ class HardwareDisplayController
   // once we no longer need it.
   ScopedDrmCrtcPtr saved_crtc_;
 
+  uint32_t current_stride_;
+
   DISALLOW_COPY_AND_ASSIGN(HardwareDisplayController);
 };
 
diff --git a/ui/ozone/platform/dri/scanout_surface.h b/ui/ozone/platform/dri/scanout_surface.h
index d362ae1..267911f 100644
--- a/ui/ozone/platform/dri/scanout_surface.h
+++ b/ui/ozone/platform/dri/scanout_surface.h
@@ -70,6 +70,9 @@ class ScanoutSurface {
 
   // Returns the surface size.
   virtual gfx::Size Size() const = 0;
+
+  // Returns the stride of the current backbuffer.
+  virtual uint32_t GetStride() const = 0;
 };
 
 class ScanoutSurfaceGenerator {