minuitwrp: drm: wait for last page flip to complete
if we try and flip pages too quickly, the kernel returns -EBUSY.
Use drmHandleEvent to wait for any previous flip to complete
before attempting a new one.
Change-Id: If3def889c0c89d7cfb8b7f13c4dae6d4b12760f9
diff --git a/minuitwrp/graphics_drm.cpp b/minuitwrp/graphics_drm.cpp
index c321bb7..aaa9e4e 100644
--- a/minuitwrp/graphics_drm.cpp
+++ b/minuitwrp/graphics_drm.cpp
@@ -42,6 +42,7 @@
static drm_surface *drm_surfaces[2];
static int current_buffer;
+static bool flip_pending = false;
static GRSurface *draw_buf = NULL;
static drmModeCrtc *main_monitor_crtc;
@@ -480,18 +481,36 @@
return draw_buf;
}
+static void drm_page_flip_event(int fd, unsigned int frame, unsigned int sec,
+ unsigned int usec, void *data) {
+ flip_pending = false;
+}
+
static GRSurface* drm_flip(minui_backend* backend __unused) {
int ret;
+ drmEventContext ev;
+
+ memset(&ev, 0, sizeof(ev));
+
memcpy(drm_surfaces[current_buffer]->base.data,
draw_buf->data, draw_buf->height * draw_buf->row_bytes);
+ ev.version = 2;
+ ev.page_flip_handler = drm_page_flip_event;
+
+ /* wait for previous page flip, if any, to complete */
+ while (flip_pending) {
+ drmHandleEvent(drm_fd, &ev);
+ }
ret = drmModePageFlip(drm_fd, main_monitor_crtc->crtc_id,
- drm_surfaces[current_buffer]->fb_id, 0, NULL);
+ drm_surfaces[current_buffer]->fb_id, DRM_MODE_PAGE_FLIP_EVENT, NULL);
if (ret < 0) {
printf("drmModePageFlip failed ret=%d\n", ret);
return NULL;
}
+
+ flip_pending = true;
current_buffer = 1 - current_buffer;
return draw_buf;
}