commit ccf00a2007a363f5847636f7b53c0c89311e09d4
author Tianjie Xu <xunchang@google.com> Tue Jun 05 17:10:23 2018 -0700
committer Tianjie Xu <xunchang@google.com> Tue Jun 05 17:10:23 2018 -0700
tree 64dd5f526e92c55a271ce2749b44c61822671018
parent 02ee7bf29dad865076132b04ff35f53dcc419da6

minui: Handle the failures from the drm backend in gr_init

In a charger mode manual test, we encounter failures from the
MinuiBackendDrm when calling DrmEnableCrtc and Flip. To make the minui
more robust, we should fall back to another backend if drm's SetCrtc
fails. And check the value of gr_draw before dereferencing.

Bug: 80249440
Test: boot to recovery
Change-Id: Ibd1ca1fb1115fe1132684586c54eccd8fb4c3ad9

minui/graphics.cpp

diff --git a/minui/graphics.cpp b/minui/graphics.cpp
index 3b38601..c1aab41 100644
--- a/minui/graphics.cpp
+++ b/minui/graphics.cpp
@@ -356,6 +356,10 @@
 
   gr_flip();
   gr_flip();
+  if (!gr_draw) {
+    printf("gr_init: gr_draw becomes nullptr after gr_flip\n");
+    return -1;
+  }
 
   gr_rotate(DEFAULT_ROTATION);
 

minui/graphics_drm.cpp

diff --git a/minui/graphics_drm.cpp b/minui/graphics_drm.cpp
index e7d4b38..4c98507 100644
--- a/minui/graphics_drm.cpp
+++ b/minui/graphics_drm.cpp
@@ -45,15 +45,17 @@
   }
 }
 
-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) {
@@ -368,7 +370,10 @@
 
   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];
 }

minui/graphics_drm.h

diff --git a/minui/graphics_drm.h b/minui/graphics_drm.h
index de96212..756625b 100644
--- a/minui/graphics_drm.h
+++ b/minui/graphics_drm.h
@@ -42,7 +42,7 @@
 
  private:
   void DrmDisableCrtc(int drm_fd, drmModeCrtc* crtc);
-  void DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface);
+  int DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface);
   GRSurfaceDrm* DrmCreateSurface(int width, int height);
   void DrmDestroySurface(GRSurfaceDrm* surface);
   void DisableNonMainCrtcs(int fd, drmModeRes* resources, drmModeCrtc* main_crtc);