sna: Expand the array of fake outputs if the last is used

Always maintain one spare so that we can reconfigure for any number of
desired outputs on the fly.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

src/sna/sna.h

@@ -265,6 +265,10 @@ struct sna {
 		DamagePtr shadow_damage;
 		struct kgem_bo *shadow;
 		int shadow_flip;
+
+		unsigned num_real_crtc;
+		unsigned num_real_output;
+		unsigned num_fake;
 	} mode;
 
 	struct sna_dri {

src/sna/sna_display.c

@@ -3211,7 +3211,7 @@ bool sna_mode_pre_init(ScrnInfoPtr scrn, struct sna *sna)
 	}
 
 	if (!xf86GetOptValInteger(sna->Options, OPTION_VIRTUAL, &num_fake))
-		num_fake = 0;
+		num_fake = 1;
 
 	mode->kmode = drmModeGetResources(sna->kgem.fd);
 	if (mode->kmode) {

src/sna/sna_display_fake.c

@@ -31,6 +31,8 @@
 
 #include "sna.h"
 
+static bool add_fake_output(struct sna *sna, bool late);
+
 static void
 sna_crtc_dpms(xf86CrtcPtr crtc, int mode)
 {
@@ -102,21 +104,6 @@ static const xf86CrtcFuncsRec sna_crtc_funcs = {
 #endif
 };
 
-static bool
-sna_crtc_fake(struct sna *sna)
-{
-	ScrnInfoPtr scrn = sna->scrn;
-	xf86CrtcPtr crtc;
-
-	DBG(("%s\n", __FUNCTION__));
-
-	crtc = xf86CrtcCreate(scrn, &sna_crtc_funcs);
-	if (crtc == NULL)
-		return false;
-
-	return true;
-}
-
 static void
 sna_output_create_resources(xf86OutputPtr output)
 {
@@ -143,8 +130,14 @@ sna_output_dpms(xf86OutputPtr output, int dpms)
 static xf86OutputStatus
 sna_output_detect(xf86OutputPtr output)
 {
-	if (output->randr_output->numUserModes)
+	if (output->randr_output->numUserModes) {
+		xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(output->scrn);
+
+		if (xf86_config->output[xf86_config->num_output-1] == output)
+			add_fake_output(to_sna(output->scrn), true);
+
 		return XF86OutputStatusConnected;
+	}
 
 	return XF86OutputStatusDisconnected;
 }
@@ -183,32 +176,6 @@ static const xf86OutputFuncsRec sna_output_funcs = {
 	.destroy = sna_output_destroy
 };
 
-static bool
-sna_output_fake(struct sna *sna, int n, int num_fake, int num_real_crtc, int num_real_output)
-{
-	ScrnInfoPtr scrn = sna->scrn;
-	xf86OutputPtr output;
-	unsigned mask;
-	char buf[80];
-
-	sprintf(buf, "VIRTUAL%d", n+1);
-	output = xf86OutputCreate(scrn, &sna_output_funcs, buf);
-	if (!output)
-		return false;
-
-	output->mm_width = 0;
-	output->mm_height = 0;
-
-	output->subpixel_order = SubPixelNone;
-
-	mask = (1 << num_fake) - 1;
-	output->possible_crtcs = mask << num_real_crtc;
-	output->possible_clones = mask << num_real_output;
-	output->interlaceAllowed = FALSE;
-
-	return true;
-}
-
 static Bool
 sna_mode_resize(ScrnInfoPtr scrn, int width, int height)
 {
@@ -251,28 +218,126 @@ static const xf86CrtcConfigFuncsRec sna_mode_funcs = {
 	sna_mode_resize
 };
 
+static bool add_fake_output(struct sna *sna, bool late)
+{
+	ScrnInfoPtr scrn = sna->scrn;
+	xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(scrn);
+	xf86OutputPtr output;
+	xf86CrtcPtr crtc;
+	RROutputPtr clones[32];
+	RRCrtcPtr crtcs[32];
+	unsigned mask;
+	char buf[80];
+	int i, j, len;
+
+	if (sna->mode.num_fake >= 32)
+		return false;
+
+	DBG(("%s(late=%d, num_fake=%d)\n", __FUNCTION__, late, sna->mode.num_fake+1));
+
+	crtc = xf86CrtcCreate(scrn, &sna_crtc_funcs);
+	if (crtc == NULL)
+		return false;
+
+	len = sprintf(buf, "VIRTUAL%d", sna->mode.num_fake+1);
+	output = xf86OutputCreate(scrn, &sna_output_funcs, buf);
+	if (!output) {
+		xf86CrtcDestroy(crtc);
+		return false;
+	}
+
+	output->mm_width = 0;
+	output->mm_height = 0;
+	output->interlaceAllowed = FALSE;
+	output->subpixel_order = SubPixelNone;
+
+	if (late) {
+		ScreenPtr screen = xf86ScrnToScreen(scrn);
+
+		crtc->randr_crtc = RRCrtcCreate(screen, crtc);
+		output->randr_output = RROutputCreate(screen, buf, len, output);
+		if (crtc->randr_crtc == NULL || output->randr_output == NULL) {
+			xf86OutputDestroy(output);
+			xf86CrtcDestroy(crtc);
+			return false;
+		}
+
+		RRPostPendingProperties(output->randr_output);
+
+		mask = (1 << ++sna->mode.num_fake) - 1;
+		for (i = j = 0; i < xf86_config->num_output; i++) {
+			output = xf86_config->output[i];
+			if (output->driver_private)
+				continue;
+
+			output->possible_crtcs = mask << sna->mode.num_real_crtc;
+			output->possible_clones = mask << sna->mode.num_real_output;
+
+			clones[j++] = output->randr_output;
+		}
+		assert(j == sna->mode.num_fake);
+
+		for (i = j = 0; i < xf86_config->num_crtc; i++) {
+			crtc = xf86_config->crtc[i];
+			if (crtc->driver_private)
+				continue;
+
+			crtcs[j++] = crtc->randr_crtc;
+		}
+		assert(j == sna->mode.num_fake);
+
+		for (i = 0; i < xf86_config->num_output; i++) {
+			output = xf86_config->output[i];
+			if (output->driver_private)
+				continue;
+
+			if (!RROutputSetCrtcs(output->randr_output, crtcs, j) ||
+			    !RROutputSetClones(output->randr_output, clones, j))
+				goto err;
+		}
+	} else {
+		mask = (1 << ++sna->mode.num_fake) - 1;
+		output->possible_crtcs = mask << sna->mode.num_real_crtc;
+		output->possible_clones = mask << sna->mode.num_real_output;
+	}
+
+	return true;
+
+err:
+	for (i = 0; i < xf86_config->num_output; i++) {
+		output = xf86_config->output[i];
+		if (output->driver_private)
+			continue;
+
+		xf86OutputDestroy(output);
+	}
+
+	for (i = 0; i < xf86_config->num_crtc; i++) {
+		crtc = xf86_config->crtc[i];
+		if (crtc->driver_private)
+			continue;
+		xf86CrtcDestroy(crtc);
+	}
+	sna->mode.num_fake = -1;
+	return false;
+}
+
 bool sna_mode_fake_init(struct sna *sna, int num_fake)
 {
 	xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(sna->scrn);
-	int n, num_real_crtc, num_real_output;
+	bool ret;
 
 	if (num_fake == 0)
 		return true;
 
-	num_real_crtc = xf86_config->num_crtc;
-	num_real_output = xf86_config->num_output;
+	sna->mode.num_real_crtc = xf86_config->num_crtc;
+	sna->mode.num_real_output = xf86_config->num_output;
 
-	if (num_real_crtc == 0)
+	if (sna->mode.num_real_crtc == 0)
 		xf86CrtcConfigInit(sna->scrn, &sna_mode_funcs);
 
-	for (n = 0; n < num_fake; n++) {
-		if (!sna_crtc_fake(sna))
-			return false;
-
-		if (!sna_output_fake(sna, n, num_fake,
-				     num_real_crtc, num_real_output))
-			return false;
-	}
-
-	return true;
+	ret = true;
+	while (ret && num_fake--)
+		ret = add_fake_output(sna, false);
+	return ret;
 }

tools/intel-virtual-output.man

@@ -5,19 +5,12 @@
 intel-virtual-output \- Utility for connecting the Integrated Intel GPU to discrete outputs
 .SH SYNOPSIS
 .nf
-.B "Section \*qDevice\*q"
-.BI "  Identifier \*q"  devname \*q
-.B  "  Driver \*qintel\*q"
-.B  "  Option \*qVirtualHeads\*q" \*q<number>\*q
-\ \ ...
-.B EndSection
-.B ""
 .B "intel-virtual-output [<remote display>] <output name>..."
 .fi
 .SH DESCRIPTION
 .B intel-virtual-output
 is a utility for Intel integrated graphics chipsets on hybrid systems.
-The tool connects pre-allocated VirtualHeads to a remote output, allowing
+The tool connects local VirtualHeads to a remote output, allowing
 the primary display to extend onto the remote outputs.
 
 .SH REPORTING BUGS

tools/virtual.c

@@ -383,6 +383,37 @@ err:
 	return ret;
 }
 
+static int claim_virtual(struct output *output)
+{
+	char buf[] = "ClaimVirtualHead";
+	XRRScreenResources *res;
+	XRRModeInfo mode;
+	RRMode id;
+
+	/* Set any mode on the VirtualHead to make the Xserver allocate another */
+	assert(output->rr_output);
+
+	memset(&mode, 0, sizeof(mode));
+	mode.width = 1024;
+	mode.height = 768;
+	mode.name = buf;
+	mode.nameLength = sizeof(buf) - 1;
+
+	id = XRRCreateMode(output->dpy, output->window, &mode);
+	XRRAddOutputMode(output->dpy, output->rr_output, id);
+
+	/* Force a redetection for the ddx to spot the new outputs */
+	res = XRRGetScreenResources(output->dpy, output->window);
+	if (res == NULL)
+		return ENOMEM;
+
+	XRRFreeScreenResources(res);
+	XRRDeleteOutputMode(output->dpy, output->rr_output, id);
+	XRRDestroyMode(output->dpy, id);
+
+	return 0;
+}
+
 static int get_current_config(struct output *output)
 {
 	XRRScreenResources *res;
@@ -1471,18 +1502,8 @@ int main(int argc, char **argv)
 
 		sprintf(buf, "VIRTUAL%d", ctx.num_clones+1);
 		ret = clone_output_init(&ctx.clones[ctx.num_clones], &ctx.clones[ctx.num_clones].src, &ctx.display[0], buf);
-		if (ret) {
-			while (++i < argc)
-				ctx.num_clones += strchr(argv[i], ':') == NULL;
-			fprintf(stderr,
-				"No preallocated VirtualHead found for argv[i].\n"
-				"Please increase the number of VirtualHeads in xorg.conf:\n"
-				"  Section \"Device\"\n"
-				"    Identifier \"<identifier>\"\n"
-				"    Driver \"intel\"\n"
-				"    Option \"VirtualHeads\" \"%d\"\n"
-				"    ...\n"
-				"  EndSection\n", ctx.num_clones+1);
+		if (ret || claim_virtual(&ctx.clones[ctx.num_clones].src)) {
+			fprintf(stderr, "Failed to find available VirtualHead for argv[i].\n");
 			return ret;
 		}