kmsdrm: implement smarter surface recreation function to be used in videomode changes. Other minor arrangements.

src/video/kmsdrm/SDL_kmsdrmmouse.c

@@ -39,17 +39,6 @@ static void KMSDRM_FreeCursor(SDL_Cursor * cursor);
 static void KMSDRM_WarpMouse(SDL_Window * window, int x, int y);
 static int KMSDRM_WarpMouseGlobal(int x, int y);
 
-/*********************************/
-/* Atomic helper functions block.*/
-/*********************************/
-
-
-
-/**************************************/
-/* Atomic helper functions block ends.*/
-/**************************************/
-
-
 /* Converts a pixel from straight-alpha [AA, RR, GG, BB], which the SDL cursor surface has,
    to premultiplied-alpha [AA. AA*RR, AA*GG, AA*BB].
    These multiplications have to be done with floats instead of uint32_t's, and the resulting values have 
@@ -398,9 +387,11 @@ KMSDRM_MoveCursor(SDL_Cursor * cursor)
        That's why we move the cursor graphic ONLY. */
     if (mouse && mouse->cur_cursor && mouse->cur_cursor->driverdata) {
         curdata = (KMSDRM_CursorData *) mouse->cur_cursor->driverdata;
-	/* In SDLPoP "QUIT?" menu, no more pageflips are generated, so no more atomic_commit() calls
-	   from SwapWindow(), causing the cursor movement requested here not to be seen on screen.
-	   Thus we have to do an atomic_commit() here, so requested movements are commited and seen. */
+        /* Some programs expect cursor movement even while they don't do SwapWindow() calls,
+           and since we ride on the atomic_commit() in SwapWindow() for cursor movement,
+           cursor won't move in these situations. We could do an atomic_commit() for each
+           cursor movement request, but it cripples the movement to 30FPS, so a future solution
+           is needed. SDLPoP "QUIT?" menu is an example of this situation. */
         ret = drm_atomic_movecursor(curdata, mouse->x, mouse->y);
         //ret = drm_atomic_commit(curdata->video, SDL_TRUE);
 

src/video/kmsdrm/SDL_kmsdrmopengles.c

@@ -115,7 +115,7 @@ KMSDRM_GLES_SwapWindow(_THIS, SDL_Window * window)
     }
     fb = KMSDRM_FBFromBO(_this, windata->next_bo);
     if (!fb) {
-	 return SDL_SetError("Failed to get a new framebuffer BO");
+	 return SDL_SetError("Failed to get a new framebuffer");
     }
 
     /* Add the pageflip to te request list. */

src/video/kmsdrm/SDL_kmsdrmvideo.c

@@ -770,9 +770,14 @@ KMSDRM_DestroySurfaces(_THIS, SDL_Window * window)
 
     /* CAUTION: Before destroying the GBM ane EGL surfaces, we must disconnect the display plane
        from the GBM surface buffer it's reading, and make it read the original buffer stored
-       on the CRTC while we recreate the GBM surface.
-       The plane will be pointed to one of the buffers of the new GBM surface on the next pageflip
-       (if there is another pageflip: we could arrive here because we are exiting the program...). */ 
+       on the CRTC while we recreate the GBM surface, OR simply set it's CRTC_ID and FB_ID props to 0.
+       Since setting CRTC_ID and FB_ID to 0 does not work on amdgpu, we point to the original
+       buffer containig the TTY instead, but it may stop working when we use KMSCON instead of
+       FBCON because there won't be an original TTY FB to go back to.
+       In the future, when KMSCON is used, just zero the props instead.
+       But ALWAYS do manual freeing here because some programs call DestroyWindow() when
+       they want to resize video, and end up here mid-game when the user changes the window size.
+    */
     drm_atomic_setbuffer(_this, dispdata->display_plane, dispdata->crtc->crtc->buffer_id);
     drm_atomic_commit(_this, SDL_TRUE);
 
@@ -824,8 +829,6 @@ KMSDRM_CreateSurfaces(_THIS, SDL_Window * window)
     egl_context = (EGLContext)SDL_GL_GetCurrentContext();
 #endif
 
-    KMSDRM_DestroySurfaces(_this, window);
-
     windata->gs = KMSDRM_gbm_surface_create(viddata->gbm_dev, width, height, surface_fmt, surface_flags);
 
     if (!windata->gs) {
@@ -847,6 +850,112 @@ KMSDRM_CreateSurfaces(_THIS, SDL_Window * window)
     return 0;
 }
 
+/* Used for videomode change, where we need to have the display plane pointing  */
+/* to a buffer of a new GBM surface BEFORE destroying the old GBM surface.      */
+int
+KMSDRM_RecreateSurfaces(_THIS, SDL_Window * window)
+{
+    SDL_VideoData *viddata = ((SDL_VideoData *)_this->driverdata);
+    SDL_WindowData *windata = (SDL_WindowData *)window->driverdata;
+    SDL_DisplayData *dispdata = (SDL_DisplayData *) SDL_GetDisplayForWindow(window)->driverdata;
+    Uint32 width = dispdata->mode.hdisplay;
+    Uint32 height = dispdata->mode.vdisplay;
+    Uint32 surface_fmt = GBM_FORMAT_ARGB8888;
+    Uint32 surface_flags = GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING;
+
+    struct gbm_surface *new_gs;
+    struct gbm_bo *bo;
+    KMSDRM_FBInfo *fb;
+    int ret;
+
+#if SDL_VIDEO_OPENGL_EGL
+    EGLContext egl_context;
+#endif
+
+    /*********************************************************************/
+    /* FIRST CREATE THE NEW GBM SURFACE AND MAKE THE PLANE READ          */
+    /* A BUFFER FROM THAT NEW GBM SURFACE...                             */
+    /*********************************************************************/
+
+    if (!KMSDRM_gbm_device_is_format_supported(viddata->gbm_dev, surface_fmt, surface_flags)) {
+        SDL_LogWarn(SDL_LOG_CATEGORY_VIDEO, "GBM surface format not supported. Trying anyway.");
+    }
+
+#if SDL_VIDEO_OPENGL_EGL
+    SDL_EGL_SetRequiredVisualId(_this, surface_fmt);
+    egl_context = (EGLContext)SDL_GL_GetCurrentContext();
+#endif
+
+    new_gs = KMSDRM_gbm_surface_create(viddata->gbm_dev, width, height, surface_fmt, surface_flags);
+
+    if (!new_gs) {
+        return SDL_SetError("Could not create new GBM surface");
+    }
+
+
+    /********************************************************/
+    /* ...THEN DESTROY THE OLD GBM SURFACE AND IT'S BUFFERS */
+    /********************************************************/
+
+    if (windata->bo) {
+        KMSDRM_gbm_surface_release_buffer(windata->gs, windata->bo);
+        windata->bo = NULL;
+    }
+
+    if (windata->next_bo) {
+        KMSDRM_gbm_surface_release_buffer(windata->gs, windata->next_bo);
+        windata->next_bo = NULL;
+    }
+
+#if SDL_VIDEO_OPENGL_EGL
+    SDL_EGL_MakeCurrent(_this, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+
+    if (windata->egl_surface != EGL_NO_SURFACE) {
+        SDL_EGL_DestroySurface(_this, windata->egl_surface);
+        windata->egl_surface = EGL_NO_SURFACE;
+    }
+#endif
+
+    if (windata->gs) {
+        KMSDRM_gbm_surface_destroy(windata->gs);
+        windata->gs = NULL;
+    }
+
+
+    /* From now on, we'll be operating our shiny, new GBM surface! */
+    windata->gs = new_gs;
+
+#if SDL_VIDEO_OPENGL_EGL
+    windata->egl_surface = SDL_EGL_CreateSurface(_this, (NativeWindowType)new_gs);
+
+    if (windata->egl_surface == EGL_NO_SURFACE) {
+        return SDL_SetError("Could not create EGL window surface");
+    }
+
+    SDL_EGL_MakeCurrent(_this, windata->egl_surface, egl_context);
+
+    windata->egl_surface_dirty = SDL_FALSE;
+#endif
+
+    bo = KMSDRM_gbm_surface_lock_front_buffer(windata->gs);
+    if (!bo) {
+	return SDL_SetError("Failed to lock frontbuffer on GBM surface recreation");
+    }
+    fb = KMSDRM_FBFromBO(_this, windata->next_bo);
+    if (!fb) {
+	 return SDL_SetError("Failed to get a new framebuffer on GBM surface recreation");
+    }
+
+    /* Issue sync pageflip to one of the buffers of the new GBM surface. */
+    drm_atomic_setbuffer(_this, dispdata->display_plane, fb->fb_id);
+    ret = drm_atomic_commit(_this, SDL_TRUE);
+    if (ret) {
+        return SDL_SetError("failed to issue atomic commit on GBM surface recreation");
+    }
+
+    return 0;
+}
+
 int
 KMSDRM_VideoInit(_THIS)
 {
@@ -1198,8 +1307,7 @@ KMSDRM_VideoQuit(_THIS)
            atomic_commit() call, hence we are explicitly calling atomic_commit() here. 
         */
 
-         drm_atomic_setbuffer(_this,  dispdata->display_plane,
-                                  dispdata->crtc->crtc->buffer_id);
+         drm_atomic_setbuffer(_this, dispdata->display_plane, dispdata->crtc->crtc->buffer_id);
 
          ret = drm_atomic_commit(_this, SDL_TRUE);
 
@@ -1307,7 +1415,6 @@ KMSDRM_SetDisplayMode(_THIS, SDL_VideoDisplay * display, SDL_DisplayMode * mode)
 {
     SDL_VideoData *viddata = (SDL_VideoData *)_this->driverdata;
     SDL_DisplayModeData *modedata = (SDL_DisplayModeData *)mode->driverdata;
-
     if (!modedata) {
         return SDL_SetError("Mode doesn't have an associated index");
     }
@@ -1319,8 +1426,7 @@ KMSDRM_SetDisplayMode(_THIS, SDL_VideoDisplay * display, SDL_DisplayMode * mode)
         SDL_Window *window = viddata->windows[i];
 
         /* Re-create GBM and EGL surfaces everytime we change the display mode. */
-        KMSDRM_DestroySurfaces(_this, window);
-        KMSDRM_CreateSurfaces(_this, window);
+        KMSDRM_RecreateSurfaces(_this, window);
 
         /* Tell app about the resize */
         SDL_SendWindowEvent(window, SDL_WINDOWEVENT_RESIZED, mode->w, mode->h);
@@ -1442,6 +1548,10 @@ KMSDRM_DestroyWindow(_THIS, SDL_Window * window)
         }
     }
 
+    /* This is the only place where we simply destroy surfaces. On SetDisplayMode(),
+       we re-create them instead, and we don't destroy the window, just resize it.
+       DestroyWindow() is ONLY called on program quit, or if a program calls it
+       explicitly, but not on videomode change. */
     KMSDRM_DestroySurfaces(_this, window);
 
     window->driverdata = NULL;

src/video/kmsdrm/SDL_kmsdrmvideo.h

@@ -37,6 +37,11 @@
 #include <EGL/eglext.h>
 #endif
 
+/* Driverdata pointers are void struct* used to store backend-specific variables
+   and info that supports the SDL-side structs like SDL Display Devices, SDL_Windows...
+   which need to be "supported" with backend-side info and mechanisms to work. */ 
+
+
 typedef struct SDL_VideoData
 {
     int devindex;               /* device index that was passed on creation */
@@ -48,7 +53,6 @@ typedef struct SDL_VideoData
     int num_windows;
 } SDL_VideoData;
 
-
 typedef struct SDL_DisplayModeData
 {
     int mode_index;
@@ -72,6 +76,7 @@ struct connector {
 	drmModePropertyRes **props_info;
 };
 
+/* More general driverdata info that gives support and substance to the SDL_Display. */
 typedef struct SDL_DisplayData
 {
     drmModeModeInfo mode;
@@ -89,12 +94,14 @@ typedef struct SDL_DisplayData
     int kms_in_fence_fd;
     int kms_out_fence_fd;
 
-    EGLSyncKHR kms_fence; /* Signaled when kms completes changes requested in atomic iotcl (pageflip, etc). */
+    EGLSyncKHR kms_fence; /* Signaled when kms completes changes        *
+                           * requested in atomic iotcl (pageflip, etc). */
+
     EGLSyncKHR gpu_fence; /* Signaled when GPU rendering is done. */
 
 } SDL_DisplayData;
 
-
+/* Driverdata info that gives KMSDRM-side support and substance to the SDL_Window. */
 typedef struct SDL_WindowData
 {
     SDL_VideoData *viddata;
@@ -114,8 +121,7 @@ typedef struct KMSDRM_FBInfo
     uint32_t fb_id;     /* DRM framebuffer ID */
 } KMSDRM_FBInfo;
 
-/* Driver-side info about the cursor. It's here so we know about it in SDL_kmsdrmvideo.c
-   because drm_atomic_setcursor() receives a KMSDRM_CursorData parameter as a cursor. */
+/* Driverdata with driver-side info about the cursor. */
 typedef struct _KMSDRM_CursorData
 {
     struct gbm_bo *bo;
@@ -134,7 +140,7 @@ KMSDRM_FBInfo *KMSDRM_FBFromBO(_THIS, struct gbm_bo *bo);
 
 /* Atomic functions that are used from SDL_kmsdrmopengles.c and SDL_kmsdrmmouse.c */
 void drm_atomic_modeset(_THIS, int mode_index);
-void drm_atomic_setbuffer(_THIS, struct plane *plane, uint32_t fb_id);
+void drm_atomic_setbuffer(_THIS, struct plane *plane, uint32_t plane_id);
 void drm_atomic_waitpending(_THIS);
 int drm_atomic_commit(_THIS, SDL_bool blocking);
 int drm_atomic_setcursor(KMSDRM_CursorData *curdata, int x, int y);