Bump version: 6.1 → 6.2

.bumpversion.cfg

@@ -1,7 +1,7 @@
 [bumpversion]
 commit = True
 tag = True
-current_version = 6.0
+current_version = 6.2
 parse = (?P<major>\d+)\.(?P<minor>\d+)
 serialize = 
 	{major}.{minor}

janus/src/logging.h

@@ -36,11 +36,3 @@
 		JANUS_LOG(LOG_ERR, "[%s/%-9s] " x_msg ": %s\n", US_PLUGIN_NAME, x_prefix, ##__VA_ARGS__, m_perror_str); \
 		free(m_perror_str); \
 	}
-
-#define US_ONCE(...) { \
-		const int m_reported = __LINE__; \
-		if (m_reported != once) { \
-			__VA_ARGS__; \
-			once = m_reported; \
-		} \
-	}

man/ustreamer-dump.1

@@ -1,6 +1,6 @@
 .\" Manpage for ustreamer-dump.
 .\" Open an issue or pull request to https://github.com/pikvm/ustreamer to correct errors or typos
-.TH USTREAMER-DUMP 1 "version 6.0" "January 2021"
+.TH USTREAMER-DUMP 1 "version 6.2" "January 2021"
 
 .SH NAME
 ustreamer-dump \- Dump uStreamer's memory sink to file

man/ustreamer.1

@@ -1,6 +1,6 @@
 .\" Manpage for ustreamer.
 .\" Open an issue or pull request to https://github.com/pikvm/ustreamer to correct errors or typos
-.TH USTREAMER 1 "version 6.0" "November 2020"
+.TH USTREAMER 1 "version 6.2" "November 2020"
 
 .SH NAME
 ustreamer \- stream MJPEG video from any V4L2 device to the network

pkg/arch/PKGBUILD

@@ -3,7 +3,7 @@
 
 
 pkgname=ustreamer
-pkgver=6.0
+pkgver=6.2
 pkgrel=1
 pkgdesc="Lightweight and fast MJPEG-HTTP streamer"
 url="https://github.com/pikvm/ustreamer"

pkg/openwrt/Makefile

@@ -6,7 +6,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ustreamer
-PKG_VERSION:=6.0
+PKG_VERSION:=6.2
 PKG_RELEASE:=1
 PKG_MAINTAINER:=Maxim Devaev <mdevaev@gmail.com>
 

python/setup.py

@@ -17,7 +17,7 @@ def _find_sources(suffix: str) -> list[str]:
 if __name__ == "__main__":
     setup(
         name="ustreamer",
-        version="6.0",
+        version="6.2",
         description="uStreamer tools",
         author="Maxim Devaev",
         author_email="mdevaev@gmail.com",

src/libs/const.h

@@ -26,7 +26,7 @@
 
 
 #define US_VERSION_MAJOR 6
-#define US_VERSION_MINOR 0
+#define US_VERSION_MINOR 2
 
 #define US_MAKE_VERSION2(_major, _minor) #_major "." #_minor
 #define US_MAKE_VERSION1(_major, _minor) US_MAKE_VERSION2(_major, _minor)

src/libs/device.c

@@ -264,7 +264,6 @@ void us_device_close(us_device_s *dev) {
 			_D_LOG_PERROR("Can't stop capturing");
 		}
 		run->streamon = false;
-		_D_LOG_DEBUG("VIDIOC_STREAMOFF successful");
 	}
 
 	if (run->hw_bufs != NULL) {
@@ -291,7 +290,6 @@ void us_device_close(us_device_s *dev) {
 		}
 		US_DELETE(run->hw_bufs, free);
 		run->n_bufs = 0;
-		_D_LOG_DEBUG("All HW buffers released");
 	}
 
 	US_CLOSE_FD(run->fd);

src/libs/frametext.c

@@ -52,6 +52,34 @@ void us_frametext_destroy(us_frametext_s *ft) {
 	free(ft);
 }
 
+/*
+Every character in the font is encoded row-wise in 8 bytes.
+The least significant bit of each byte corresponds to the first pixel in a row. 
+The character 'A' (0x41 / 65) is encoded as { 0x0C, 0x1E, 0x33, 0x33, 0x3F, 0x33, 0x33, 0x00}
+
+    0x0C => 0000 1100 => ..XX....
+    0X1E => 0001 1110 => .XXXX...
+    0x33 => 0011 0011 => XX..XX..
+    0x33 => 0011 0011 => XX..XX..
+    0x3F => 0011 1111 => xxxxxx..
+    0x33 => 0011 0011 => XX..XX..
+    0x33 => 0011 0011 => XX..XX..
+    0x00 => 0000 0000 => ........
+
+To access the nth pixel in a row, right-shift by n.
+
+                         . . X X . . . .
+                         | | | | | | | |
+    (0x0C >> 0) & 1 == 0-+ | | | | | | |
+    (0x0C >> 1) & 1 == 0---+ | | | | | |
+    (0x0C >> 2) & 1 == 1-----+ | | | | |
+    (0x0C >> 3) & 1 == 1-------+ | | | |
+    (0x0C >> 4) & 1 == 0---------+ | | |
+    (0x0C >> 5) & 1 == 0-----------+ | |
+    (0x0C >> 6) & 1 == 0-------------+ |
+    (0x0C >> 7) & 1 == 0---------------+
+*/
+
 void us_frametext_draw(us_frametext_s *ft, const char *text, uint width, uint height) {
 	assert(width > 0);
 	assert(height > 0);

src/libs/frametext_font.c

@@ -27,6 +27,8 @@
 
 const u8 US_FRAMETEXT_FONT[128][8] = {
 	// https://github.com/dhepper/font8x8/blob/master/font8x8_basic.h
+	// Author: Daniel Hepper <daniel@hepper.net>
+	// License: Public Domain
 	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, // U+0000 (nul)
 	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, // U+0001
 	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, // U+0002

src/libs/tools.h

@@ -72,6 +72,14 @@
 		(m_a > m_b ? m_a : m_b); \
 	})
 
+#define US_ONCE(...) { \
+		const int m_reported = __LINE__; \
+		if (m_reported != once) { \
+			__VA_ARGS__; \
+			once = m_reported; \
+		} \
+	}
+
 
 INLINE char *us_strdup(const char *str) {
 	char *const new = strdup(str);

src/ustreamer/stream.c

@@ -177,12 +177,11 @@ void us_stream_loop(us_stream_s *stream) {
 		uint slowdown_count = 0;
 		while (!atomic_load(&run->stop) && !atomic_load(&threads_stop)) {
 			us_hw_buffer_s *hw;
-			const int buf_index = us_device_grab_buffer(dev, &hw);
-			switch (buf_index) {
+			switch (us_device_grab_buffer(dev, &hw)) {
 				case -2: continue; // Broken frame
 				case -1: goto close; // Error
+				default: break; // Grabbed on >= 0
 			}
-			assert(buf_index >= 0);
 
 			const sll now_sec_ts = us_floor_ms(us_get_now_monotonic());
 			if (now_sec_ts != captured_fps_ts) {
@@ -208,7 +207,7 @@ void us_stream_loop(us_stream_s *stream) {
 				us_device_buffer_incref(hw); // RAW
 				us_queue_put(raw_ctx.queue, hw, 0);
 			}
-			us_queue_put(releasers[buf_index].queue, hw, 0); // Plan to release
+			us_queue_put(releasers[hw->buf.index].queue, hw, 0); // Plan to release
 
 			// Мы не обновляем здесь состояние синков, потому что это происходит внутри обслуживающих их потоков
 			_stream_check_suicide(stream);

src/v4p/drm.c

@@ -44,15 +44,14 @@
 #include "../libs/frametext.h"
 
 
-static void _drm_vsync_callback(int fd, uint n_frame, uint sec, uint usec, void *v_run);
-static int _drm_expose_raw(us_drm_s *drm, const us_frame_s *frame);
-static void _drm_cleanup(us_drm_s *drm);
-static int _drm_ensure(us_drm_s *drm, const us_frame_s *frame, float hz);
+static void _drm_vsync_callback(int fd, uint n_frame, uint sec, uint usec, void *v_buf);
 static int _drm_check_status(us_drm_s *drm);
+static void _drm_ensure_dpms_power(us_drm_s *drm, bool on);
+static int _drm_init_buffers(us_drm_s *drm, const us_device_s *dev);
 static int _drm_find_sink(us_drm_s *drm, uint width, uint height, float hz);
-static int _drm_init_buffers(us_drm_s *drm);
-static int _drm_start_video(us_drm_s *drm);
 
+static drmModeModeInfo *_find_best_mode(drmModeConnector *conn, uint width, uint height, float hz);
+static u32 _find_dpms(int fd, drmModeConnector *conn);
 static u32 _find_crtc(int fd, drmModeRes *res, drmModeConnector *conn, u32 *taken_crtcs);
 static const char *_connector_type_to_string(u32 type);
 static float _get_refresh_rate(const drmModeModeInfo *mode);
@@ -70,33 +69,203 @@ us_drm_s *us_drm_init(void) {
 	US_CALLOC(run, 1);
 	run->fd = -1;
 	run->status_fd = -1;
+	run->dpms_state = -1;
+	run->has_vsync = true;
+	run->exposing_dma_fd = -1;
 	run->ft = us_frametext_init();
-	run->state = US_DRM_STATE_CLOSED;
 
 	us_drm_s *drm;
 	US_CALLOC(drm, 1);
 	// drm->path = "/dev/dri/card0";
 	drm->path = "/dev/dri/by-path/platform-gpu-card";
 	drm->port = "HDMI-A-1";
-	drm->n_bufs = 4;
 	drm->timeout = 5;
 	drm->run = run;
 	return drm;
 }
 
 void us_drm_destroy(us_drm_s *drm) {
-	_drm_cleanup(drm);
 	us_frametext_destroy(drm->run->ft);
 	US_DELETE(drm->run, free);
 	US_DELETE(drm, free); // cppcheck-suppress uselessAssignmentPtrArg
 }
 
+int us_drm_open(us_drm_s *drm, const us_device_s *dev) {
+	us_drm_runtime_s *const run = drm->run;
+
+	assert(run->fd < 0);
+
+	switch (_drm_check_status(drm)) {
+		case 0: break;
+		case -2: goto unplugged;
+		default: goto error;
+	}
+
+	_D_LOG_INFO("Configuring DRM device for %s ...", (dev == NULL ? "STUB" : "DMA"));
+
+	if ((run->fd = open(drm->path, O_RDWR | O_CLOEXEC | O_NONBLOCK)) < 0) {
+		_D_LOG_PERROR("Can't open DRM device");
+		goto error;
+	}
+	_D_LOG_DEBUG("DRM device fd=%d opened", run->fd);
+
+	int stub = 0; // Open the real device with DMA
+	if (dev == NULL) {
+		stub = US_DRM_STUB_USER;
+	} else if (dev->run->format != V4L2_PIX_FMT_RGB24) {
+		stub = US_DRM_STUB_BAD_FORMAT;
+		char fourcc_str[8];
+		us_fourcc_to_string(dev->run->format, fourcc_str, 8);
+		_D_LOG_ERROR("Input format %s is not supported, forcing to STUB ...", fourcc_str);
+	}
+
+#	define CHECK_CAP(x_cap) { \
+			_D_LOG_DEBUG("Checking %s ...", #x_cap); \
+			u64 m_check; \
+			if (drmGetCap(run->fd, x_cap, &m_check) < 0) { \
+				_D_LOG_PERROR("Can't check " #x_cap); \
+				goto error; \
+			} \
+			if (!m_check) { \
+				_D_LOG_ERROR(#x_cap " is not supported"); \
+				goto error; \
+			} \
+		}
+	CHECK_CAP(DRM_CAP_DUMB_BUFFER);
+	if (stub == 0) {
+		CHECK_CAP(DRM_CAP_PRIME);
+	}
+#	undef CHECK_CAP
+
+	const uint width = (stub > 0 ? 0 : dev->run->width);
+	const uint height = (stub > 0 ? 0 : dev->run->height);
+	const uint hz = (stub > 0 ? 0 : dev->run->hz);
+	switch (_drm_find_sink(drm, width, height, hz)) {
+		case 0: break;
+		case -2: goto unplugged;
+		default: goto error;
+	}
+	if ((stub == 0) && (width != run->mode.hdisplay || height < run->mode.vdisplay)) {
+		// We'll try to show something instead of nothing if height != vdisplay
+		stub = US_DRM_STUB_BAD_RESOLUTION;
+		_D_LOG_ERROR("There is no appropriate modes for the capture, forcing to STUB ...");
+	}
+
+	if (_drm_init_buffers(drm, (stub > 0 ? NULL : dev)) < 0) {
+		goto error;
+	}
+
+	run->saved_crtc = drmModeGetCrtc(run->fd, run->crtc_id);
+	_D_LOG_DEBUG("Setting up CRTC ...");
+	if (drmModeSetCrtc(run->fd, run->crtc_id, run->bufs[0].id, 0, 0, &run->conn_id, 1, &run->mode) < 0) {
+		_D_LOG_PERROR("Can't set CRTC");
+		goto error;
+	}
+
+	run->opened_for_stub = (stub > 0);
+	run->exposing_dma_fd = -1;
+	run->unplugged_reported = false;
+	_D_LOG_INFO("Opened for %s ...", (run->opened_for_stub ? "STUB" : "DMA"));
+	return stub;
+
+error:
+	us_drm_close(drm);
+	return -1;
+
+unplugged:
+	if (!run->unplugged_reported) {
+		_D_LOG_ERROR("Display is not plugged");
+		run->unplugged_reported = true;
+	}
+	us_drm_close(drm);
+	return -2;
+}
+
+void us_drm_close(us_drm_s *drm) {
+	us_drm_runtime_s *const run = drm->run;
+
+	if (run->exposing_dma_fd >= 0) {
+		// Нужно подождать, пока dma_fd не освободится, прежде чем прерывать процесс.
+		// Просто на всякий случай.
+		assert(run->fd >= 0);
+		us_drm_wait_for_vsync(drm);
+		run->exposing_dma_fd = -1;
+	}
+
+	if (run->saved_crtc != NULL) {
+		_D_LOG_DEBUG("Restoring CRTC ...");
+		if (drmModeSetCrtc(run->fd,
+			run->saved_crtc->crtc_id, run->saved_crtc->buffer_id,
+			run->saved_crtc->x, run->saved_crtc->y,
+			&run->conn_id, 1, &run->saved_crtc->mode
+		) < 0 && errno != ENOENT) {
+			_D_LOG_PERROR("Can't restore CRTC");
+		}
+		drmModeFreeCrtc(run->saved_crtc);
+		run->saved_crtc = NULL;
+	}
+
+	if (run->bufs != NULL) {
+		_D_LOG_DEBUG("Releasing buffers ...");
+		for (uint n_buf = 0; n_buf < run->n_bufs; ++n_buf) {
+			us_drm_buffer_s *const buf = &run->bufs[n_buf];
+			if (buf->fb_added && drmModeRmFB(run->fd, buf->id) < 0) {
+				_D_LOG_PERROR("Can't remove buffer=%u", n_buf);
+			}
+			if (buf->dumb_created) {
+				struct drm_mode_destroy_dumb destroy = {.handle = buf->handle};
+				if (drmIoctl(run->fd, DRM_IOCTL_MODE_DESTROY_DUMB, &destroy) < 0) {
+					_D_LOG_PERROR("Can't destroy dumb buffer=%u", n_buf);
+				}
+			}
+			if (buf->data != NULL && munmap(buf->data, buf->allocated)) {
+				_D_LOG_PERROR("Can't unmap buffer=%u", n_buf);
+			}
+		}
+		US_DELETE(run->bufs, free);
+		run->n_bufs = 0;
+	}
+
+	const bool say = (run->fd >= 0);
+	US_CLOSE_FD(run->status_fd);
+	US_CLOSE_FD(run->fd);
+
+	run->crtc_id = 0;
+	run->dpms_state = -1;
+	run->has_vsync = true;
+	run->stub_n_buf = 0;
+
+	if (say) {
+		_D_LOG_INFO("Closed");
+	}
+}
+
+int us_drm_dpms_power_off(us_drm_s *drm) {
+	assert(drm->run->fd >= 0);
+	switch (_drm_check_status(drm)) {
+		case 0: break;
+		case -2: return 0; // Unplugged, nice
+		// Во время переключения DPMS монитор моргает один раз состоянием disconnected,
+		// а потом почему-то снова оказывается connected. Так что просто считаем,
+		// что отсоединенный монитор на этом этапе - это нормально.
+		default: return -1;
+	}
+	_drm_ensure_dpms_power(drm, false);
+	return 0;
+}
+
 int us_drm_wait_for_vsync(us_drm_s *drm) {
 	us_drm_runtime_s *const run = drm->run;
 
-	if (_drm_ensure(drm, NULL, 0) < 0) {
-		return -1;
+	assert(run->fd >= 0);
+
+	switch (_drm_check_status(drm)) {
+		case 0: break;
+		case -2: return -2;
+		default: return -1;
 	}
+	_drm_ensure_dpms_power(drm, true);
+
 	if (run->has_vsync) {
 		return 0;
 	}
@@ -110,10 +279,10 @@ int us_drm_wait_for_vsync(us_drm_s *drm) {
 	const int result = select(run->fd + 1, &fds, NULL, NULL, &timeout);
 	if (result < 0) {
 		_D_LOG_PERROR("Can't select(%d) device for VSync", run->fd);
-		goto error;
+		return -1;
 	} else if (result == 0) {
 		_D_LOG_ERROR("Device timeout while waiting VSync");
-		goto error;
+		return -1;
 	}
 
 	drmEventContext ctx = {
@@ -123,274 +292,152 @@ int us_drm_wait_for_vsync(us_drm_s *drm) {
 	_D_LOG_DEBUG("Handling DRM event (maybe VSync) ...");
 	if (drmHandleEvent(run->fd, &ctx) < 0) {
 		_D_LOG_PERROR("Can't handle DRM event");
-		goto error;
-	}
-	return 0;
-
-error:
-	_drm_cleanup(drm);
-	_D_LOG_ERROR("Device destroyed due an error (vsync)");
-	return -1;
-}
-
-int us_drm_expose(us_drm_s *drm, us_drm_expose_e ex, const us_frame_s *frame, float hz) {
-	us_drm_runtime_s *const run = drm->run;
-
-	if (_drm_ensure(drm, frame, hz) < 0) {
 		return -1;
 	}
-
-	const drmModeModeInfo *const mode = &run->mode;
-	bool msg_drawn = false;
-
-#	define DRAW_MSG(x_msg) { \
-			us_frametext_draw(run->ft, (x_msg), mode->hdisplay, mode->vdisplay); \
-			frame = run->ft->frame; \
-			msg_drawn = true; \
-		}
-
-	if (frame == NULL) {
-		switch (ex) {
-			case US_DRM_EXPOSE_NO_SIGNAL:
-				DRAW_MSG("=== PiKVM ===\n \n< NO SIGNAL >");
-				break;
-			case US_DRM_EXPOSE_BUSY:
-				DRAW_MSG("=== PiKVM ===\n \n< ONLINE IS ACTIVE >");
-				break;
-			default:
-				DRAW_MSG("=== PiKVM ===\n \n< ??? >");
-		}
-	} else if (mode->hdisplay != frame->width/* || mode->vdisplay != frame->height*/) {
-		// XXX: At least we'll try to show something instead of nothing ^^^
-		char msg[1024];
-		US_SNPRINTF(msg, 1023,
-			"=== PiKVM ==="
-			"\n \n< UNSUPPORTED RESOLUTION >"
-			"\n \n< %ux%up%.02f >"
-			"\n \nby this display",
-			frame->width, frame->height, hz);
-		DRAW_MSG(msg);
-	} else if (frame->format != V4L2_PIX_FMT_RGB24) {
-		DRAW_MSG(
-			"=== PiKVM ==="
-			"\n \n< UNSUPPORTED CAPTURE FORMAT >"
-			"\n \nIt shouldn't happen ever."
-			"\n \nPlease check the logs and report a bug:"
-			"\n \n- https://github.com/pikvm/pikvm -");
-	}
-
-#	undef DRAW_MSG
-
-	if (_drm_expose_raw(drm, frame) < 0) {
-		_drm_cleanup(drm);
-		_D_LOG_ERROR("Device destroyed due an error (expose)");
-	}
-	return (msg_drawn ? -1 : 0);
+	return 0;
 }
 
-static void _drm_vsync_callback(int fd, uint n_frame, uint sec, uint usec, void *v_run) {
+static void _drm_vsync_callback(int fd, uint n_frame, uint sec, uint usec, void *v_buf) {
 	(void)fd;
 	(void)n_frame;
 	(void)sec;
 	(void)usec;
-	us_drm_runtime_s *const run = v_run;
-	run->has_vsync = true;
+	us_drm_buffer_s *const buf = v_buf;
+	*buf->ctx.has_vsync = true;
+	*buf->ctx.exposing_dma_fd = -1;
 	_D_LOG_DEBUG("Got VSync signal");
 }
 
-static int _drm_expose_raw(us_drm_s *drm, const us_frame_s *frame) {
-	us_drm_runtime_s *const run = drm->run;
-	us_drm_buffer_s *const buf = &run->bufs[run->next_n_buf];
-
-	_D_LOG_DEBUG("Exposing%s framebuffer n_buf=%u, vsync=%d ...",
-		(frame == NULL ? " EMPTY" : ""), run->next_n_buf, run->has_vsync);
-
-	if (frame == NULL) {
-		memset(buf->data, 0, buf->allocated);
-	} else {
-		memcpy(buf->data, frame->data, US_MIN(frame->used, buf->allocated));
-	}
-
-	run->has_vsync = false;
-	const int retval = drmModePageFlip(
-		run->fd, run->crtc_id, buf->id,
-		DRM_MODE_PAGE_FLIP_EVENT | DRM_MODE_PAGE_FLIP_ASYNC,
-		run);
-	run->next_n_buf = (run->next_n_buf + 1) % run->n_bufs;
-	return retval;
-}
-
-static void _drm_cleanup(us_drm_s *drm) {
+int us_drm_expose_stub(us_drm_s *drm, us_drm_stub_e stub, const us_device_s *dev) {
 	us_drm_runtime_s *const run = drm->run;
 
-	_D_LOG_DEBUG("Cleaning up ...");
-
-	if (run->saved_crtc != NULL) {
-		if (drmModeSetCrtc(run->fd,
-			run->saved_crtc->crtc_id, run->saved_crtc->buffer_id,
-			run->saved_crtc->x, run->saved_crtc->y,
-			&run->conn_id, 1, &run->saved_crtc->mode
-		) < 0 && errno != ENOENT) {
-			_D_LOG_PERROR("Can't restore CRTC");
-		}
-		drmModeFreeCrtc(run->saved_crtc);
-		run->saved_crtc = NULL;
-	}
-
-	if (run->bufs != NULL) {
-		for (uint n_buf = 0; n_buf < run->n_bufs; ++n_buf) {
-			us_drm_buffer_s *const buf = &run->bufs[n_buf];
-			if (buf->data != NULL && munmap(buf->data, buf->allocated)) {
-				_D_LOG_PERROR("Can't unmap buffer=%u", n_buf);
-			}
-			if (buf->fb_added && drmModeRmFB(run->fd, buf->id) < 0) {
-				_D_LOG_PERROR("Can't remove buffer=%u", n_buf);
-			}
-			if (buf->dumb_created) {
-				struct drm_mode_destroy_dumb destroy = {.handle = buf->handle};
-				if (drmIoctl(run->fd, DRM_IOCTL_MODE_DESTROY_DUMB, &destroy) < 0) {
-					_D_LOG_PERROR("Can't destroy dumb buffer=%u", n_buf);
-				}
-			}
-		}
-		US_DELETE(run->bufs, free);
-		run->n_bufs = 0;
-	}
-
-	US_CLOSE_FD(run->status_fd);
-	US_CLOSE_FD(run->fd);
-
-	run->crtc_id = 0;
-	run->next_n_buf = 0;
-	run->has_vsync = false;
-	if (run->state == US_DRM_STATE_OK) {
-		_D_LOG_INFO("Stopped");
-	}
-	run->state = US_DRM_STATE_CLOSED;
-}
-
-static int _drm_ensure(us_drm_s *drm, const us_frame_s *frame, float hz) {
-	us_drm_runtime_s *const run = drm->run;
+	assert(run->fd >= 0);
+	assert(run->opened_for_stub);
 
 	switch (_drm_check_status(drm)) {
 		case 0: break;
-		case -2: goto unplugged;
-		default: goto error;
+		case -2: return -2;
+		default: return -1;
 	}
+	_drm_ensure_dpms_power(drm, true);
 
-	if (frame == NULL && run->state == US_DRM_STATE_OK) {
-		return 0;
-	} else if (
-		frame != NULL
-		&& run->p_width == frame->width
-		&& run->p_height == frame->height
-		&& run->p_hz == hz
-		&& run->state <= US_DRM_STATE_CLOSED
-	) {
-		return (run->state == US_DRM_STATE_OK ? 0 : -1);
+#	define DRAW_MSG(x_msg) us_frametext_draw(run->ft, (x_msg), run->mode.hdisplay, run->mode.vdisplay)
+	switch (stub) {
+		case US_DRM_STUB_BAD_RESOLUTION: {
+			assert(dev != NULL);
+			char msg[1024];
+			US_SNPRINTF(msg, 1023,
+				"=== PiKVM ==="
+				"\n \n< UNSUPPORTED RESOLUTION >"
+				"\n \n< %ux%up%.02f >"
+				"\n \nby this display",
+				dev->run->width, dev->run->height, dev->run->hz);
+			DRAW_MSG(msg);
+			break;
+		};
+		case US_DRM_STUB_BAD_FORMAT:
+			DRAW_MSG(
+				"=== PiKVM ==="
+				"\n \n< UNSUPPORTED CAPTURE FORMAT >"
+				"\n \nIt shouldn't happen ever."
+				"\n \nPlease check the logs and report a bug:"
+				"\n \n- https://github.com/pikvm/pikvm -");
+			break;
+		case US_DRM_STUB_NO_SIGNAL:
+			DRAW_MSG("=== PiKVM ===\n \n< NO SIGNAL >");
+			break;
+		case US_DRM_STUB_BUSY:
+			DRAW_MSG("=== PiKVM ===\n \n< ONLINE IS ACTIVE >");
+			break;
+		default:
+			DRAW_MSG("=== PiKVM ===\n \n< ??? >");
+			break;
 	}
+#	undef DRAW_MSG
 
-	const us_drm_state_e saved_state = run->state;
-	_drm_cleanup(drm);
-	if (saved_state > US_DRM_STATE_CLOSED) {
-		run->state = saved_state;
+	us_drm_buffer_s *const buf = &run->bufs[run->stub_n_buf];
+
+	run->has_vsync = false;
+
+	_D_LOG_DEBUG("Copying STUB frame ...")
+	memcpy(buf->data, run->ft->frame->data, US_MIN(run->ft->frame->used, buf->allocated));
+
+	_D_LOG_DEBUG("Exposing STUB framebuffer n_buf=%u ...", run->stub_n_buf);
+	const int retval = drmModePageFlip(
+		run->fd, run->crtc_id, buf->id,
+		DRM_MODE_PAGE_FLIP_EVENT | DRM_MODE_PAGE_FLIP_ASYNC,
+		buf);
+	if (retval < 0) {
+		_D_LOG_PERROR("Can't expose STUB framebuffer n_buf=%u ...", run->stub_n_buf);
 	}
+	_D_LOG_DEBUG("Exposed STUB framebuffer n_buf=%u", run->stub_n_buf);
 
-	run->p_width = (frame != NULL ? frame->width : 0); // 0 for find the native resolution
-	run->p_height = (frame != NULL ? frame->height : 0);
-	run->p_hz = hz;
+	run->stub_n_buf = (run->stub_n_buf + 1) % run->n_bufs;
+	return retval;
+}
 
-	_D_LOG_INFO("Configuring DRM device ...");
+int us_drm_expose_dma(us_drm_s *drm, const us_hw_buffer_s *hw) {
+	us_drm_runtime_s *const run = drm->run;
+	us_drm_buffer_s *const buf = &run->bufs[hw->buf.index];
 
-	if ((run->fd = open(drm->path, O_RDWR | O_CLOEXEC | O_NONBLOCK)) < 0) {
-		_D_LOG_PERROR("Can't open DRM device");
-		goto error;
-	}
+	assert(run->fd >= 0);
+	assert(!run->opened_for_stub);
 
-#	define CHECK_CAP(x_cap) { \
-			u64 m_check; \
-			if (drmGetCap(run->fd, x_cap, &m_check) < 0) { \
-				_D_LOG_PERROR("Can't check " #x_cap); \
-				goto error; \
-			} \
-			if (!m_check) { \
-				_D_LOG_ERROR(#x_cap " is not supported"); \
-				goto error; \
-			} \
-		}
-	CHECK_CAP(DRM_CAP_DUMB_BUFFER);
-	// CHECK_CAP(DRM_CAP_PRIME);
-#	undef CHECK_CAP
-
-	switch (_drm_find_sink(drm, run->p_width, run->p_height, run->p_hz)) {
+	switch (_drm_check_status(drm)) {
 		case 0: break;
-		case -2: goto unplugged;
-		default: goto error;
+		case -2: return -2;
+		default: return -1;
 	}
+	_drm_ensure_dpms_power(drm, true);
 
-	const float mode_hz = _get_refresh_rate(&run->mode);
-	if (frame == NULL) {
-		run->p_width = run->mode.hdisplay;
-		run->p_height = run->mode.vdisplay;
-		run->p_hz = mode_hz;
+	run->has_vsync = false;
+
+	_D_LOG_DEBUG("Exposing DMA framebuffer n_buf=%u ...", hw->buf.index);
+	const int retval = drmModePageFlip(
+		run->fd, run->crtc_id, buf->id,
+		DRM_MODE_PAGE_FLIP_EVENT | DRM_MODE_PAGE_FLIP_ASYNC,
+		buf);
+	if (retval < 0) {
+		_D_LOG_PERROR("Can't expose DMA framebuffer n_buf=%u ...", run->stub_n_buf);
 	}
-	_D_LOG_INFO("Using %s mode: %ux%up%.02f",
-		drm->port, run->mode.hdisplay, run->mode.vdisplay, mode_hz);
-
-	if (_drm_init_buffers(drm) < 0) {
-		goto error;
-	}
-
-	if (_drm_start_video(drm) < 0) {
-		goto error;
-	}
-
-	_D_LOG_INFO("Showing ...");
-	run->state = US_DRM_STATE_OK;
-	return 0;
-
-error:
-	_drm_cleanup(drm);
-	_D_LOG_ERROR("Device destroyed due an error (ensure)");
-	return -1;
-
-unplugged:
-	if (run->state != US_DRM_STATE_NO_DISPLAY) {
-		_D_LOG_INFO("Display %s is not plugged", drm->port);
-	}
-	_drm_cleanup(drm);
-	run->state = US_DRM_STATE_NO_DISPLAY;
-	return -2;
+	_D_LOG_DEBUG("Exposed DMA framebuffer n_buf=%u", run->stub_n_buf);
+	run->exposing_dma_fd = hw->dma_fd;
+	return retval;
 }
 
 static int _drm_check_status(us_drm_s *drm) {
 	us_drm_runtime_s *run = drm->run;
 
 	if (run->status_fd < 0) {
+		_D_LOG_DEBUG("Trying to find status file ...");
 		struct stat st;
 		if (stat(drm->path, &st) < 0) {
 			_D_LOG_PERROR("Can't stat() DRM device");
 			goto error;
 		}
 		const uint mi = minor(st.st_rdev);
+		_D_LOG_DEBUG("DRM device minor(st_rdev)=%u", mi);
 
 		char path[128];
 		US_SNPRINTF(path, 127, "/sys/class/drm/card%u-%s/status", mi, drm->port);
+		_D_LOG_DEBUG("Opening status file %s ...", path);
 		if ((run->status_fd = open(path, O_RDONLY | O_CLOEXEC)) < 0) {
-			_D_LOG_PERROR("Can't open DRM device status file: %s", path);
+			_D_LOG_PERROR("Can't open status file: %s", path);
 			goto error;
 		}
+		_D_LOG_DEBUG("Status file fd=%d opened", run->status_fd);
 	}
 
 	char status_ch;
 	if (read(run->status_fd, &status_ch, 1) != 1) {
-		_D_LOG_PERROR("Can't read connector status");
+		_D_LOG_PERROR("Can't read status file");
 		goto error;
 	}
 	if (lseek(run->status_fd, 0, SEEK_SET) != 0) {
-		_D_LOG_PERROR("Can't rewind connector status");
+		_D_LOG_PERROR("Can't rewind status file");
 		goto error;
 	}
+	_D_LOG_DEBUG("Current display status: %c", status_ch);
 	return (status_ch == 'd' ? -2 : 0);
 
 error:
@@ -398,6 +445,94 @@ error:
 	return -1;
 }
 
+static void _drm_ensure_dpms_power(us_drm_s *drm, bool on) {
+	us_drm_runtime_s *const run = drm->run;
+	if (run->dpms_id > 0 && run->dpms_state != (int)on) {
+		_D_LOG_INFO("Changing DPMS power mode: %d -> %u ...", run->dpms_state, on);
+		if (drmModeConnectorSetProperty(
+			run->fd, run->conn_id, run->dpms_id,
+			(on ? DRM_MODE_DPMS_ON : DRM_MODE_DPMS_OFF)
+		) < 0) {
+			_D_LOG_PERROR("Can't set DPMS power=%u (ignored)", on);
+		}
+	}
+	run->dpms_state = (int)on;
+}
+
+static int _drm_init_buffers(us_drm_s *drm, const us_device_s *dev) {
+	us_drm_runtime_s *const run = drm->run;
+
+	const uint n_bufs = (dev == NULL ? 4 : dev->run->n_bufs);
+	const char *name = (dev == NULL ? "STUB" : "DMA");
+
+	_D_LOG_DEBUG("Initializing %u %s buffers ...", n_bufs, name);
+
+	US_CALLOC(run->bufs, n_bufs);
+	for (run->n_bufs = 0; run->n_bufs < n_bufs; ++run->n_bufs) {
+		const uint n_buf = run->n_bufs;
+		us_drm_buffer_s *const buf = &run->bufs[n_buf];
+
+		buf->ctx.has_vsync = &run->has_vsync;
+		buf->ctx.exposing_dma_fd = &run->exposing_dma_fd;
+
+		u32 handles[4] = {0};
+		u32 strides[4] = {0};
+		u32 offsets[4] = {0};
+
+		if (dev == NULL) {
+			struct drm_mode_create_dumb create = {
+				.width = run->mode.hdisplay,
+				.height = run->mode.vdisplay,
+				.bpp = 24,
+			};
+			if (drmIoctl(run->fd, DRM_IOCTL_MODE_CREATE_DUMB, &create) < 0) {
+				_D_LOG_PERROR("Can't create %s buffer=%u", name, n_buf);
+				return -1;
+			}
+			buf->handle = create.handle;
+			buf->dumb_created = true;
+
+			struct drm_mode_map_dumb map = {.handle = create.handle};
+			if (drmIoctl(run->fd, DRM_IOCTL_MODE_MAP_DUMB, &map) < 0) {
+				_D_LOG_PERROR("Can't prepare dumb buffer=%u to mapping", n_buf);
+				return -1;
+			}
+			if ((buf->data = mmap(
+				NULL, create.size,
+				PROT_READ | PROT_WRITE, MAP_SHARED,
+				run->fd, map.offset
+			)) == MAP_FAILED) {
+				_D_LOG_PERROR("Can't map buffer=%u", n_buf);
+				return -1;
+			}
+			memset(buf->data, 0, create.size);
+			buf->allocated = create.size;
+
+			handles[0] = create.handle;
+			strides[0] = create.pitch;
+
+		} else {
+			if (drmPrimeFDToHandle(run->fd, dev->run->hw_bufs[n_buf].dma_fd, &buf->handle) < 0) {
+				_D_LOG_PERROR("Can't import DMA buffer=%u from capture device", n_buf);
+				return -1;
+			}
+			handles[0] = buf->handle;
+			strides[0] = dev->run->stride;
+		}
+
+		if (drmModeAddFB2(
+			run->fd,
+			run->mode.hdisplay, run->mode.vdisplay, DRM_FORMAT_RGB888,
+			handles, strides, offsets, &buf->id, 0
+		)) {
+			_D_LOG_PERROR("Can't setup buffer=%u", n_buf);
+			return -1;
+		}
+		buf->fb_added = true;
+	}
+	return 0;
+}
+
 static int _drm_find_sink(us_drm_s *drm, uint width, uint height, float hz) {
 	us_drm_runtime_s *const run = drm->run;
 
@@ -430,49 +565,29 @@ static int _drm_find_sink(us_drm_s *drm, uint width, uint height, float hz) {
 			drmModeFreeConnector(conn);
 			continue;
 		}
-		_D_LOG_DEBUG("Found connector for port %s: conn_type=%d, conn_type_id=%d",
+		_D_LOG_INFO("Using connector %s: conn_type=%d, conn_type_id=%d",
 			drm->port, conn->connector_type, conn->connector_type_id);
 
 		if (conn->connection != DRM_MODE_CONNECTED) {
-			_D_LOG_DEBUG("Display is not connected");
+			_D_LOG_ERROR("Connector for port %s has !DRM_MODE_CONNECTED", drm->port);
 			drmModeFreeConnector(conn);
 			goto done;
 		}
 
-		drmModeModeInfo *best = NULL;
-		drmModeModeInfo *closest = NULL;
-		drmModeModeInfo *pref = NULL;
-		for (int mi = 0; mi < conn->count_modes; ++mi) {
-			drmModeModeInfo *const mode = &conn->modes[mi];
-			if (mode->flags & DRM_MODE_FLAG_INTERLACE) {
-				continue; // Paranoia for size and discard interlaced
-			}
-			const float mode_hz = _get_refresh_rate(mode);
-			if (mode->hdisplay == width && mode->vdisplay == height) {
-				best = mode; // Any mode with exact resolution
-				if (hz > 0 && mode_hz == hz) {
-					break; // Exact mode with same freq
-				}
-			}
-			if (mode->hdisplay == width && mode->vdisplay < height) {
-				if (closest == NULL || _get_refresh_rate(closest) != hz) {
-					closest = mode; // Something like 1920x1080p60 for 1920x1200p60 source
-				}
-			}
-			if (pref == NULL && (mode->type & DRM_MODE_TYPE_PREFERRED)) {
-				pref = mode; // Preferred mode if nothing is found
-			}
-		}
-		if (best == NULL) { best = closest; }
-		if (best == NULL) { best = pref; }
-		if (best == NULL) { best = (conn->count_modes > 0 ? &conn->modes[0] : NULL); }
-		if (best == NULL) {
-			_D_LOG_ERROR("Can't find any appropriate resolutions");
+		drmModeModeInfo *best;
+		if ((best = _find_best_mode(conn, width, height, hz)) == NULL) {
+			_D_LOG_ERROR("Can't find any appropriate display modes");
 			drmModeFreeConnector(conn);
 			goto unplugged;
 		}
-		assert(best->hdisplay > 0);
-		assert(best->vdisplay > 0);
+		_D_LOG_INFO("Using best mode: %ux%up%.02f",
+			best->hdisplay, best->vdisplay, _get_refresh_rate(best));
+
+		if ((run->dpms_id = _find_dpms(run->fd, conn)) > 0) {
+			_D_LOG_INFO("Using DPMS: id=%u", run->dpms_id);
+		} else {
+			_D_LOG_INFO("Using DPMS: None");
+		}
 
 		u32 taken_crtcs = 0; // Unused here
 		if ((run->crtc_id = _find_crtc(run->fd, res, conn, &taken_crtcs)) == 0) {
@@ -480,6 +595,8 @@ static int _drm_find_sink(us_drm_s *drm, uint width, uint height, float hz) {
 			drmModeFreeConnector(conn);
 			goto done;
 		}
+		_D_LOG_INFO("Using CRTC: id=%u", run->crtc_id);
+
 		run->conn_id = conn->connector_id;
 		memcpy(&run->mode, best, sizeof(drmModeModeInfo));
 
@@ -496,72 +613,58 @@ unplugged:
 	return -2;
 }
 
-static int _drm_init_buffers(us_drm_s *drm) {
-	us_drm_runtime_s *const run = drm->run;
+static drmModeModeInfo *_find_best_mode(drmModeConnector *conn, uint width, uint height, float hz) {
+	drmModeModeInfo *best = NULL;
+	drmModeModeInfo *closest = NULL;
+	drmModeModeInfo *pref = NULL;
 
-	_D_LOG_DEBUG("Initializing %u buffers ...", drm->n_bufs);
-
-	US_CALLOC(run->bufs, drm->n_bufs);
-	for (run->n_bufs = 0; run->n_bufs < drm->n_bufs; ++run->n_bufs) {
-		const uint n_buf = run->n_bufs;
-		us_drm_buffer_s *const buf = &run->bufs[n_buf];
-
-		struct drm_mode_create_dumb create = {
-			.width = run->mode.hdisplay,
-			.height = run->mode.vdisplay,
-			.bpp = 24,
-		};
-		if (drmIoctl(run->fd, DRM_IOCTL_MODE_CREATE_DUMB, &create) < 0) {
-			_D_LOG_PERROR("Can't create dumb buffer=%u", n_buf);
-			return -1;
+	for (int mi = 0; mi < conn->count_modes; ++mi) {
+		drmModeModeInfo *const mode = &conn->modes[mi];
+		if (mode->flags & DRM_MODE_FLAG_INTERLACE) {
+			continue; // Discard interlaced
 		}
-		buf->handle = create.handle;
-		buf->dumb_created = true;
-
-		u32 handles[4] = {create.handle};
-		u32 strides[4] = {create.pitch};
-		u32 offsets[4] = {0};
-		if (drmModeAddFB2(
-			run->fd,
-			run->mode.hdisplay, run->mode.vdisplay, DRM_FORMAT_RGB888,
-			handles, strides, offsets, &buf->id, 0
-		)) {
-			_D_LOG_PERROR("Can't setup buffer=%u", n_buf);
-			return -1;
+		const float mode_hz = _get_refresh_rate(mode);
+		if (mode->hdisplay == width && mode->vdisplay == height) {
+			best = mode; // Any mode with exact resolution
+			if (hz > 0 && mode_hz == hz) {
+				break; // Exact mode with same freq
+			}
 		}
-		buf->fb_added = true;
-
-		struct drm_mode_map_dumb map = {.handle = create.handle};
-		if (drmIoctl(run->fd, DRM_IOCTL_MODE_MAP_DUMB, &map) < 0) {
-			_D_LOG_PERROR("Can't prepare dumb buffer=%u to mapping", n_buf);
-			return -1;
+		if (mode->hdisplay == width && mode->vdisplay < height) {
+			if (closest == NULL || _get_refresh_rate(closest) != hz) {
+				closest = mode; // Something like 1920x1080p60 for 1920x1200p60 source
+			}
 		}
-
-		if ((buf->data = mmap(
-			NULL, create.size,
-			PROT_READ | PROT_WRITE, MAP_SHARED,
-			run->fd, map.offset
-		)) == MAP_FAILED) {
-			_D_LOG_PERROR("Can't map buffer=%u", n_buf);
-			return -1;
+		if (pref == NULL && (mode->type & DRM_MODE_TYPE_PREFERRED)) {
+			pref = mode; // Preferred mode if nothing is found
 		}
-		memset(buf->data, 0, create.size);
-		buf->allocated = create.size;
 	}
-	return 0;
+
+	if (best == NULL) {
+		best = closest;
+	}
+	if (best == NULL) {
+		best = pref;
+	}
+	if (best == NULL) {
+		best = (conn->count_modes > 0 ? &conn->modes[0] : NULL);
+	}
+	assert(best == NULL || best->hdisplay > 0);
+	assert(best == NULL || best->vdisplay > 0);
+	return best;
 }
 
-static int _drm_start_video(us_drm_s *drm) {
-	us_drm_runtime_s *const run = drm->run;
-	run->saved_crtc = drmModeGetCrtc(run->fd, run->crtc_id);
-	_D_LOG_DEBUG("Setting up CRTC ...");
-	if (drmModeSetCrtc(run->fd, run->crtc_id, run->bufs[0].id, 0, 0, &run->conn_id, 1, &run->mode) < 0) {
-		_D_LOG_PERROR("Can't set CRTC");
-		return -1;
-	}
-	if (_drm_expose_raw(drm, NULL) < 0) {
-		_D_LOG_PERROR("Can't flip the first page");
-		return -1;
+static u32 _find_dpms(int fd, drmModeConnector *conn) {
+	for (int pi = 0; pi < conn->count_props; pi++) {
+		drmModePropertyPtr prop = drmModeGetProperty(fd, conn->props[pi]);
+		if (prop != NULL) {
+			if (!strcmp(prop->name, "DPMS")) {
+				const u32 id = prop->prop_id;
+				drmModeFreeProperty(prop);
+				return id;
+			}
+			drmModeFreeProperty(prop);
+		}
 	}
 	return 0;
 }

src/v4p/drm.h

@@ -28,19 +28,16 @@
 #include "../libs/types.h"
 #include "../libs/frame.h"
 #include "../libs/frametext.h"
+#include "../libs/device.h"
 
 
 typedef enum {
-	US_DRM_EXPOSE_FRAME = 0,
-	US_DRM_EXPOSE_NO_SIGNAL,
-	US_DRM_EXPOSE_BUSY,
-} us_drm_expose_e;
-
-typedef enum {
-	US_DRM_STATE_OK = 0,
-	US_DRM_STATE_CLOSED,
-	US_DRM_STATE_NO_DISPLAY,
-} us_drm_state_e;
+	US_DRM_STUB_USER = 1,
+	US_DRM_STUB_BAD_RESOLUTION,
+	US_DRM_STUB_BAD_FORMAT,
+	US_DRM_STUB_NO_SIGNAL,
+	US_DRM_STUB_BUSY,
+} us_drm_stub_e;
 
 typedef struct {
 	u32		id;
@@ -49,34 +46,34 @@ typedef struct {
 	uz		allocated;
 	bool	dumb_created;
 	bool	fb_added;
+	struct {
+		bool	*has_vsync;
+		int		*exposing_dma_fd;
+	} ctx;
 } us_drm_buffer_s;
 
 typedef struct {
 	int				status_fd;
-
 	int				fd;
 	u32				crtc_id;
 	u32				conn_id;
+	u32				dpms_id;
 	drmModeModeInfo	mode;
 	us_drm_buffer_s	*bufs;
 	uint			n_bufs;
 	drmModeCrtc		*saved_crtc;
-	uint			next_n_buf;
+	int				dpms_state;
+	bool			opened_for_stub;
 	bool			has_vsync;
-
+	int				exposing_dma_fd;
+	uint			stub_n_buf;
+	bool			unplugged_reported;
 	us_frametext_s	*ft;
-
-	uint			p_width;
-	uint			p_height;
-	float			p_hz;
-
-	us_drm_state_e	state;
 } us_drm_runtime_s;
 
 typedef struct {
 	char	*path;
 	char	*port;
-	uint	n_bufs;
 	uint	timeout;
 
 	us_drm_runtime_s *run;
@@ -86,5 +83,10 @@ typedef struct {
 us_drm_s *us_drm_init(void);
 void us_drm_destroy(us_drm_s *drm);
 
+int us_drm_open(us_drm_s *drm, const us_device_s *dev);
+void us_drm_close(us_drm_s *drm);
+
+int us_drm_dpms_power_off(us_drm_s *drm);
 int us_drm_wait_for_vsync(us_drm_s *drm);
-int us_drm_expose(us_drm_s *drm, us_drm_expose_e ex, const us_frame_s *frame, float hz);
+int us_drm_expose_stub(us_drm_s *drm, us_drm_stub_e stub, const us_device_s *dev);
+int us_drm_expose_dma(us_drm_s *drm, const us_hw_buffer_s *hw);

src/v4p/main.c

@@ -164,62 +164,97 @@ static void _main_loop(void) {
 
 	us_device_s *dev = us_device_init();
 	dev->path = "/dev/kvmd-video";
-	dev->n_bufs = drm->n_bufs;
+	dev->n_bufs = 6;
 	dev->format = V4L2_PIX_FMT_RGB24;
 	dev->dv_timings = true;
 	dev->persistent = true;
+	dev->dma_export = true;
+	dev->dma_required = true;
 
+	int once = 0;
+	ldf blank_at_ts = 0;
+	int drm_opened = -1;
 	while (!atomic_load(&_g_stop)) {
+#		define CHECK(x_arg) if ((x_arg) < 0) { goto close; }
+
+		if (drm_opened <= 0) {
+			blank_at_ts = 0;
+			CHECK(drm_opened = us_drm_open(drm, NULL));
+		}
+		assert(drm_opened > 0);
+
 		if (atomic_load(&_g_ustreamer_online)) {
-			if (us_drm_wait_for_vsync(drm) == 0) {
-				us_drm_expose(drm, US_DRM_EXPOSE_BUSY, NULL, 0);
-			}
-			if (dev->run->fd >= 0) {
-				goto close;
-			} else {
-				_slowdown();
-				continue;
-			}
+			blank_at_ts = 0;
+			US_ONCE({ US_LOG_INFO("DRM: Online stream is active, stopping capture ..."); });
+			CHECK(us_drm_wait_for_vsync(drm));
+			CHECK(us_drm_expose_stub(drm, US_DRM_STUB_BUSY, NULL));
+			_slowdown();
+			continue;
 		}
 
 		if (us_device_open(dev) < 0) {
-			if (us_drm_wait_for_vsync(drm) == 0) {
-				us_drm_expose(drm, US_DRM_EXPOSE_NO_SIGNAL, NULL, 0);
+			ldf now_ts = us_get_now_monotonic();
+			if (blank_at_ts == 0) {
+				blank_at_ts = now_ts + 5;
 			}
-			goto close;
+			if (now_ts <= blank_at_ts) {
+				CHECK(us_drm_wait_for_vsync(drm));
+				CHECK(us_drm_expose_stub(drm, US_DRM_STUB_NO_SIGNAL, NULL));
+			} else {
+				US_ONCE({ US_LOG_INFO("DRM: Turning off the display by timeout ..."); });
+				CHECK(us_drm_dpms_power_off(drm));
+			}
+			_slowdown();
+			continue;
 		}
 
+		once = 0;
+		blank_at_ts = 0;
+		us_drm_close(drm);
+		CHECK(drm_opened = us_drm_open(drm, dev));
+
+		us_hw_buffer_s *prev_hw = NULL;
 		while (!atomic_load(&_g_stop)) {
 			if (atomic_load(&_g_ustreamer_online)) {
 				goto close;
 			}
 
-			if (us_drm_wait_for_vsync(drm) < 0) {
-				_slowdown();
-				continue;
+			CHECK(us_drm_wait_for_vsync(drm));
+
+			if (prev_hw != NULL) {
+				CHECK(us_device_release_buffer(dev, prev_hw));
+				prev_hw = NULL;
 			}
 
 			us_hw_buffer_s *hw;
-			const int buf_index = us_device_grab_buffer(dev, &hw);
-			switch (buf_index) {
+			switch (us_device_grab_buffer(dev, &hw)) {
 				case -2: continue; // Broken frame
 				case -1: goto close; // Any error
+				default: break; // Grabbed on >= 0
 			}
-			assert(buf_index >= 0);
 
-			const int exposed = us_drm_expose(drm, US_DRM_EXPOSE_FRAME, &hw->raw, dev->run->hz);
-			if (us_device_release_buffer(dev, hw) < 0) {
-				goto close;
+			if (drm_opened == 0) {
+				CHECK(us_drm_expose_dma(drm, hw));
+				prev_hw = hw;
+			} else {
+				CHECK(us_drm_expose_stub(drm, drm_opened, dev));
+				CHECK(us_device_release_buffer(dev, hw));
 			}
-			if (exposed < 0) {
+
+			if (drm_opened > 0) {
 				_slowdown();
-				continue;
 			}
 		}
 
 	close:
+		us_drm_close(drm);
+		drm_opened = -1;
+
 		us_device_close(dev);
+
 		_slowdown();
+
+#		undef CHECK
 	}
 
 	us_device_destroy(dev);