1 files changed, 69 insertions, 23 deletions

diff --git a/minui/graphics_drm.cpp b/minui/graphics_drm.cpp
index e7d4b38ef..81b49fd95 100644
--- a/minui/graphics_drm.cpp
+++ b/minui/graphics_drm.cpp
@@ -17,6 +17,7 @@
 #include "graphics_drm.h"
 
 #include <fcntl.h>
+#include <poll.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/mman.h>
@@ -45,15 +46,17 @@ void MinuiBackendDrm::DrmDisableCrtc(int drm_fd, drmModeCrtc* crtc) {
   }
 }
 
-void MinuiBackendDrm::DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface) {
-  int32_t ret = drmModeSetCrtc(drm_fd, crtc->crtc_id, surface->fb_id, 0, 0,  // x,y
-                               &main_monitor_connector->connector_id,
-                               1,  // connector_count
-                               &main_monitor_crtc->mode);
+int MinuiBackendDrm::DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface) {
+  int ret = drmModeSetCrtc(drm_fd, crtc->crtc_id, surface->fb_id, 0, 0,  // x,y
+                           &main_monitor_connector->connector_id,
+                           1,  // connector_count
+                           &main_monitor_crtc->mode);
 
   if (ret) {
     printf("drmModeSetCrtc failed ret=%d\n", ret);
   }
+
+  return ret;
 }
 
 void MinuiBackendDrm::Blank(bool blank) {
@@ -67,8 +70,8 @@ void MinuiBackendDrm::Blank(bool blank) {
 void MinuiBackendDrm::DrmDestroySurface(GRSurfaceDrm* surface) {
   if (!surface) return;
 
-  if (surface->data) {
-    munmap(surface->data, surface->row_bytes * surface->height);
+  if (surface->mmapped_buffer_) {
+    munmap(surface->mmapped_buffer_, surface->row_bytes * surface->height);
   }
 
   if (surface->fb_id) {
@@ -113,15 +116,20 @@ GRSurfaceDrm* MinuiBackendDrm::DrmCreateSurface(int width, int height) {
   *surface = {};
 
   uint32_t format;
-#if defined(RECOVERY_ABGR)
-  format = DRM_FORMAT_RGBA8888;
-#elif defined(RECOVERY_BGRA)
-  format = DRM_FORMAT_ARGB8888;
-#elif defined(RECOVERY_RGBX)
-  format = DRM_FORMAT_XBGR8888;
-#else
-  format = DRM_FORMAT_RGB565;
-#endif
+  PixelFormat pixel_format = gr_pixel_format();
+  // PixelFormat comes in byte order, whereas DRM_FORMAT_* uses little-endian
+  // (external/libdrm/include/drm/drm_fourcc.h). Note that although drm_fourcc.h also defines a
+  // macro of DRM_FORMAT_BIG_ENDIAN, it doesn't seem to be actually supported (see the discussion
+  // in https://lists.freedesktop.org/archives/amd-gfx/2017-May/008560.html).
+  if (pixel_format == PixelFormat::ABGR) {
+    format = DRM_FORMAT_RGBA8888;
+  } else if (pixel_format == PixelFormat::BGRA) {
+    format = DRM_FORMAT_ARGB8888;
+  } else if (pixel_format == PixelFormat::RGBX) {
+    format = DRM_FORMAT_XBGR8888;
+  } else {
+    format = DRM_FORMAT_RGB565;
+  }
 
   drm_mode_create_dumb create_dumb = {};
   create_dumb.height = height;
@@ -164,15 +172,14 @@ GRSurfaceDrm* MinuiBackendDrm::DrmCreateSurface(int width, int height) {
   surface->width = width;
   surface->row_bytes = create_dumb.pitch;
   surface->pixel_bytes = create_dumb.bpp / 8;
-  surface->data = static_cast<unsigned char*>(mmap(nullptr, surface->height * surface->row_bytes,
-                                                   PROT_READ | PROT_WRITE, MAP_SHARED, drm_fd,
-                                                   map_dumb.offset));
-  if (surface->data == MAP_FAILED) {
+  auto mmapped = mmap(nullptr, surface->height * surface->row_bytes, PROT_READ | PROT_WRITE,
+                      MAP_SHARED, drm_fd, map_dumb.offset);
+  if (mmapped == MAP_FAILED) {
     perror("mmap() failed");
     DrmDestroySurface(surface);
     return nullptr;
   }
-
+  surface->mmapped_buffer_ = static_cast<uint8_t*>(mmapped);
   return surface;
 }
 
@@ -368,18 +375,57 @@ GRSurface* MinuiBackendDrm::Init() {
 
   current_buffer = 0;
 
-  DrmEnableCrtc(drm_fd, main_monitor_crtc, GRSurfaceDrms[1]);
+  // We will likely encounter errors in the backend functions (i.e. Flip) if EnableCrtc fails.
+  if (DrmEnableCrtc(drm_fd, main_monitor_crtc, GRSurfaceDrms[1]) != 0) {
+    return nullptr;
+  }
 
   return GRSurfaceDrms[0];
 }
 
+static void page_flip_complete(__unused int fd,
+                               __unused unsigned int sequence,
+                               __unused unsigned int tv_sec,
+                               __unused unsigned int tv_usec,
+                               void *user_data) {
+  *static_cast<bool*>(user_data) = false;
+}
+
 GRSurface* MinuiBackendDrm::Flip() {
+  bool ongoing_flip = true;
+
   int ret = drmModePageFlip(drm_fd, main_monitor_crtc->crtc_id,
-                            GRSurfaceDrms[current_buffer]->fb_id, 0, nullptr);
+                            GRSurfaceDrms[current_buffer]->fb_id,
+                            DRM_MODE_PAGE_FLIP_EVENT, &ongoing_flip);
   if (ret < 0) {
     printf("drmModePageFlip failed ret=%d\n", ret);
     return nullptr;
   }
+
+  while (ongoing_flip) {
+    struct pollfd fds = {
+      .fd = drm_fd,
+      .events = POLLIN
+    };
+
+    ret = poll(&fds, 1, -1);
+    if (ret == -1 || !(fds.revents & POLLIN)) {
+      printf("poll() failed on drm fd\n");
+      break;
+    }
+
+    drmEventContext evctx = {
+      .version = DRM_EVENT_CONTEXT_VERSION,
+      .page_flip_handler = page_flip_complete
+    };
+
+    ret = drmHandleEvent(drm_fd, &evctx);
+    if (ret != 0) {
+      printf("drmHandleEvent failed ret=%d\n", ret);
+      break;
+    }
+  }
+
   current_buffer = 1 - current_buffer;
   return GRSurfaceDrms[current_buffer];
 }