Merge pull request #969 from yshui/detect-dpms-off

.github/workflows/codeql-analysis.yml

@@ -36,7 +36,7 @@ jobs:
         languages: ${{ matrix.language }}
 
     # Install dependencies
-    - run: sudo apt update && sudo apt install libxext-dev libxcb1-dev libxcb-damage0-dev libxcb-xfixes0-dev libxcb-shape0-dev libxcb-render-util0-dev libxcb-render0-dev libxcb-randr0-dev libxcb-composite0-dev libxcb-image0-dev libxcb-present-dev libxcb-xinerama0-dev libxcb-glx0-dev libpixman-1-dev libdbus-1-dev libconfig-dev libgl1-mesa-dev  libpcre2-dev  libevdev-dev uthash-dev libev-dev libx11-xcb-dev meson ninja-build
+    - run: sudo apt update && sudo apt install libxext-dev libxcb1-dev libxcb-dpms0-dev libxcb-damage0-dev libxcb-xfixes0-dev libxcb-shape0-dev libxcb-render-util0-dev libxcb-render0-dev libxcb-randr0-dev libxcb-composite0-dev libxcb-image0-dev libxcb-present-dev libxcb-xinerama0-dev libxcb-glx0-dev libpixman-1-dev libdbus-1-dev libconfig-dev libgl1-mesa-dev  libpcre2-dev  libevdev-dev uthash-dev libev-dev libx11-xcb-dev meson ninja-build
       if: ${{ matrix.language == 'cpp' }}
 
     # Autobuild

README.md

@@ -23,6 +23,7 @@ Assuming you already have all the usual building tools installed (e.g. gcc, pyth
 * xproto
 * xcb
 * xcb-damage
+* xcb-dpms
 * xcb-xfixes
 * xcb-shape
 * xcb-renderutil
@@ -44,7 +45,7 @@ Assuming you already have all the usual building tools installed (e.g. gcc, pyth
 On Debian based distributions (e.g. Ubuntu), the needed packages are
 
 ```
-libxext-dev libxcb1-dev libxcb-damage0-dev libxcb-xfixes0-dev libxcb-shape0-dev libxcb-render-util0-dev libxcb-render0-dev libxcb-randr0-dev libxcb-composite0-dev libxcb-image0-dev libxcb-present-dev libxcb-xinerama0-dev libxcb-glx0-dev libpixman-1-dev libdbus-1-dev libconfig-dev libgl-dev libegl-dev libpcre2-dev libevdev-dev uthash-dev libev-dev libx11-xcb-dev meson
+libxext-dev libxcb1-dev libxcb-damage0-dev libxcb-dpms0-dev libxcb-xfixes0-dev libxcb-shape0-dev libxcb-render-util0-dev libxcb-render0-dev libxcb-randr0-dev libxcb-composite0-dev libxcb-image0-dev libxcb-present-dev libxcb-xinerama0-dev libxcb-glx0-dev libpixman-1-dev libdbus-1-dev libconfig-dev libgl-dev libegl-dev libpcre2-dev libevdev-dev uthash-dev libev-dev libx11-xcb-dev meson
 ```
 
 On Fedora, the needed packages are

src/common.h

@@ -150,6 +150,8 @@ typedef struct session {
 	// === Event handlers ===
 	/// ev_io for X connection
 	ev_io xiow;
+	/// Timer for checking DPMS power level
+	ev_timer dpms_check_timer;
 	/// Timeout for delayed unredirection.
 	ev_timer unredir_timer;
 	/// Timer for fading
@@ -236,6 +238,8 @@ typedef struct session {
 	xcb_sync_fence_t sync_fence;
 	/// Whether we are rendering the first frame after screen is redirected
 	bool first_frame;
+	/// Whether screen has been turned off
+	bool screen_is_off;
 
 	// === Operation related ===
 	/// Flags related to the root window
@@ -342,6 +346,8 @@ typedef struct session {
 	int composite_error;
 	/// Major opcode for X Composite extension.
 	int composite_opcode;
+	/// Whether X DPMS extension exists
+	bool dpms_exists;
 	/// Whether X Shape extension exists.
 	bool shape_exists;
 	/// Event base number for X Shape extension.

src/meson.build

@@ -16,7 +16,8 @@ cflags = []
 
 required_xcb_packages = [
 	'xcb-render', 'xcb-damage', 'xcb-randr', 'xcb-sync', 'xcb-composite',
-	'xcb-shape', 'xcb-xinerama', 'xcb-xfixes', 'xcb-present', 'xcb-glx', 'xcb'
+	'xcb-shape', 'xcb-xinerama', 'xcb-xfixes', 'xcb-present', 'xcb-glx', 
+	'xcb-dpms', 'xcb'
 ]
 
 required_packages = [

src/picom.c

@@ -21,6 +21,7 @@
 #include <unistd.h>
 #include <xcb/composite.h>
 #include <xcb/damage.h>
+#include <xcb/dpms.h>
 #include <xcb/glx.h>
 #include <xcb/present.h>
 #include <xcb/randr.h>
@@ -169,6 +170,26 @@ void cxinerama_upd_scrs(session_t *ps) {
 	free(xinerama_scrs);
 }
 
+static inline bool dpms_screen_is_off(xcb_dpms_info_reply_t *info) {
+	// state is a bool indicating whether dpms is enabled
+	return info->state && (info->power_level != XCB_DPMS_DPMS_MODE_ON);
+}
+
+void check_dpms_status(EV_P attr_unused, ev_timer *w, int revents attr_unused) {
+	auto ps = session_ptr(w, dpms_check_timer);
+	auto r = xcb_dpms_info_reply(ps->c, xcb_dpms_info(ps->c), NULL);
+	if (!r) {
+		log_fatal("Failed to query DPMS status.");
+		abort();
+	}
+	auto now_screen_is_off = dpms_screen_is_off(r);
+	if (ps->screen_is_off != now_screen_is_off) {
+		ps->screen_is_off = now_screen_is_off;
+		queue_redraw(ps);
+	}
+	free(r);
+}
+
 /**
  * Find matched window.
  *
@@ -920,6 +941,19 @@ paint_preprocess(session_t *ps, bool *fade_running, bool *animation) {
 		// If there's no window to paint, and the screen isn't redirected,
 		// don't redirect it.
 		unredir_possible = true;
+	} else if (ps->screen_is_off) {
+		// Screen is off, unredirect
+		// We do this unconditionally disregarding "unredir_if_possible"
+		// because it's important for correctness, because we need to
+		// workaround problems X server has around screen off.
+		//
+		// Known problems:
+		//   1. Sometimes OpenGL front buffer can lose content, and if we
+		//      are doing partial updates (i.e. use-damage = true), the
+		//      result will be wrong.
+		//   2. For frame pacing, X server sends bogus
+		//      PresentCompleteNotify events when screen is off.
+		unredir_possible = true;
 	}
 	if (unredir_possible) {
 		if (ps->redirected) {
@@ -1800,6 +1834,7 @@ static session_t *session_init(int argc, char **argv, Display *dpy,
 	xcb_prefetch_extension_data(ps->c, &xcb_present_id);
 	xcb_prefetch_extension_data(ps->c, &xcb_sync_id);
 	xcb_prefetch_extension_data(ps->c, &xcb_glx_id);
+	xcb_prefetch_extension_data(ps->c, &xcb_dpms_id);
 
 	ext_info = xcb_get_extension_data(ps->c, &xcb_render_id);
 	if (!ext_info || !ext_info->present) {
@@ -1868,6 +1903,21 @@ static session_t *session_init(int argc, char **argv, Display *dpy,
 		ps->glx_event = ext_info->first_event;
 	}
 
+	ext_info = xcb_get_extension_data(ps->c, &xcb_dpms_id);
+	ps->dpms_exists = ext_info && ext_info->present;
+	if (ps->dpms_exists) {
+		auto r = xcb_dpms_info_reply(ps->c, xcb_dpms_info(ps->c), NULL);
+		if (!r) {
+			log_fatal("Failed to query DPMS info");
+			goto err;
+		}
+		ps->screen_is_off = dpms_screen_is_off(r);
+		// Check screen status every half second
+		ev_timer_init(&ps->dpms_check_timer, check_dpms_status, 0, 0.5);
+		ev_timer_start(ps->loop, &ps->dpms_check_timer);
+		free(r);
+	}
+
 	// Parse configuration file
 	win_option_mask_t winopt_mask[NUM_WINTYPES] = {{0}};
 	bool shadow_enabled = false, fading_enable = false, hasneg = false;
@@ -2462,6 +2512,7 @@ static void session_destroy(session_t *ps) {
 	// Stop libev event handlers
 	ev_timer_stop(ps->loop, &ps->unredir_timer);
 	ev_timer_stop(ps->loop, &ps->fade_timer);
+	ev_timer_stop(ps->loop, &ps->dpms_check_timer);
 	ev_idle_stop(ps->loop, &ps->draw_idle);
 	ev_prepare_stop(ps->loop, &ps->event_check);
 	ev_signal_stop(ps->loop, &ps->usr1_signal);