sna: Add zaphod support

Zaphod support is a rudimentary method for creating an Xserver with
multiple screens from a single device. The Device is instantiated, with
a duplication of its resources, as many as required up to a maximum of
the number of its outputs, and each instance is attached to a Screen
and added to the ServerLayout. A Device can be bound to a selection of
outputs using a comma separated list of RandR names.

Note: in general, this is not the preferred solution! And will be
superseded by per-crtc-pixmaps in RandR-1.4.

For example, the following xorg.conf fragment creates an XServer with
two screens, one attached to the LVDS panel on the laptop, and the other
to any external output:

Section "Device"
	Identifier "Intel0"
	Driver     "intel"
	BusID	   "PCI:0:2:0"
	Option     "ZaphodHeads" "LVDS1"
	Screen     0
EndSection

Section "Device"
	Identifier "Intel1"
	Driver     "intel"
	BusID	   "PCI:0:2:0"
	Option     "ZaphodHeads" "DVI1,VGA1"
	Screen     1
EndSection

Section "Screen"
	Identifier "Screen0"
	Device     "Intel0"
EndSection

Section "Screen"
	Identifier "Screen1"
	Device     "Intel1"
EndSection

Section "ServerLayout"
	Identifier "default"
	Screen     "Screen0"
	Screen     "Screen1"
EndSection

Based on a patch by Ben Skegs <bskeggs@redhat.com>

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

man/intel.man

@@ -222,6 +222,16 @@ This option controls whether the driver automatically notifies
 applications when monitors are connected or disconnected.
 .IP
 Default: enabled.
+.BI "Option \*qZaphodHeads\*q \*q" string \*q
+.IP
+Specify the randr output(s) to use with zaphod mode for a particular driver
+instance.  If you this option you must use it with all instances of the
+driver
+.br
+For example:
+.B
+Option \*qZaphodHeads\*q \*qLVDS1,VGA1\*q
+will assign xrandr outputs LVDS1 and VGA0 to this instance of the driver.
 
 .SH OUTPUT CONFIGURATION
 On 830M and better chipsets, the driver supports runtime configuration of

src/intel_module.c

@@ -363,12 +363,12 @@ static Bool intel_pci_probe(DriverPtr		driver,
 		case PCI_CHIP_SANDYBRIDGE_M_GT2_PLUS:
 		case PCI_CHIP_SANDYBRIDGE_S_GT:
 #endif
-			sna_init_scrn(scrn);
+			sna_init_scrn(scrn, entity_num);
 			break;
 #endif
 		default:
 #if SNA_DEFAULT
-			sna_init_scrn(scrn);
+			sna_init_scrn(scrn, entity_num);
 #else
 			intel_init_scrn(scrn);
 #endif

src/sna/sna.h

@@ -201,6 +201,7 @@ enum {
 	OPTION_THROTTLE,
 	OPTION_RELAXED_FENCING,
 	OPTION_VMAP,
+	OPTION_ZAPHOD,
 };
 
 enum {

src/sna/sna_display.c

@@ -1231,6 +1231,43 @@ static const char *output_names[] = {
 	"eDP",
 };
 
+static bool
+sna_zaphod_match(ScrnInfoPtr scrn, const char *s, const char *output)
+{
+	char t[20];
+	int i = 0;
+
+	do {
+		/* match any outputs in a comma list, stopping at whitespace */
+		switch (*s) {
+		case '\0':
+			t[i] = '\0';
+			return strcmp(t, output) == 0;
+
+		case ',':
+			t[i] ='\0';
+			if (strcmp(t, output) == 0)
+				return TRUE;
+			i = 0;
+			break;
+
+		case ' ':
+		case '\t':
+		case '\n':
+		case '\r':
+			break;
+
+		default:
+			t[i++] = *s;
+			break;
+		}
+
+		s++;
+	} while (i < sizeof(t));
+
+	return FALSE;
+}
+
 static void
 sna_output_init(ScrnInfoPtr scrn, struct sna_mode *mode, int num)
 {
@@ -1240,6 +1277,7 @@ sna_output_init(ScrnInfoPtr scrn, struct sna_mode *mode, int num)
 	drmModeEncoderPtr kencoder;
 	struct sna_output *sna_output;
 	const char *output_name;
+	const char *s;
 	char name[32];
 
 	koutput = drmModeGetConnector(sna->kgem.fd,
@@ -1248,10 +1286,8 @@ sna_output_init(ScrnInfoPtr scrn, struct sna_mode *mode, int num)
 		return;
 
 	kencoder = drmModeGetEncoder(sna->kgem.fd, koutput->encoders[0]);
-	if (!kencoder) {
-		drmModeFreeConnector(koutput);
-		return;
-	}
+	if (!kencoder)
+		goto cleanup_connector;
 
 	if (koutput->connector_type < ARRAY_SIZE(output_names))
 		output_name = output_names[koutput->connector_type];
@@ -1259,20 +1295,22 @@ sna_output_init(ScrnInfoPtr scrn, struct sna_mode *mode, int num)
 		output_name = "UNKNOWN";
 	snprintf(name, 32, "%s%d", output_name, koutput->connector_type_id);
 
-	output = xf86OutputCreate (scrn, &sna_output_funcs, name);
-	if (!output) {
-		drmModeFreeEncoder(kencoder);
-		drmModeFreeConnector(koutput);
-		return;
+	if (xf86IsEntityShared(scrn->entityList[0])) {
+		s = xf86GetOptValString(sna->Options, OPTION_ZAPHOD);
+		if (s && !sna_zaphod_match(scrn, s, name)) {
+			ErrorF("output '%s' not matched for zaphod '%s'\n",
+			       name, s);
+			goto cleanup_encoder;
+		}
 	}
 
+	output = xf86OutputCreate(scrn, &sna_output_funcs, name);
+	if (!output)
+		goto cleanup_encoder;
+
 	sna_output = calloc(sizeof(struct sna_output), 1);
-	if (!sna_output) {
-		xf86OutputDestroy(output);
-		drmModeFreeConnector(koutput);
-		drmModeFreeEncoder(kencoder);
-		return;
-	}
+	if (!sna_output)
+		goto cleanup_output;
 
 	sna_output->output_id = mode->mode_res->connectors[num];
 	sna_output->mode_output = koutput;
@@ -1294,6 +1332,15 @@ sna_output_init(ScrnInfoPtr scrn, struct sna_mode *mode, int num)
 
 	sna_output->output = output;
 	list_add(&sna_output->link, &mode->outputs);
+
+	return;
+
+cleanup_output:
+	xf86OutputDestroy(output);
+cleanup_connector:
+	drmModeFreeConnector(koutput);
+cleanup_encoder:
+	drmModeFreeEncoder(kencoder);
 }
 
 struct sna_visit_set_pixmap_window {

src/sna/sna_driver.c

@@ -81,6 +81,7 @@ static OptionInfoRec sna_options[] = {
    {OPTION_THROTTLE,	"Throttle",	OPTV_BOOLEAN,	{0},	TRUE},
    {OPTION_RELAXED_FENCING,	"UseRelaxedFencing",	OPTV_BOOLEAN,	{0},	TRUE},
    {OPTION_VMAP,	"UseVmap",	OPTV_BOOLEAN,	{0},	TRUE},
+   {OPTION_ZAPHOD,	"ZaphodHeads",	OPTV_STRING,	{0},	FALSE},
    {-1,			NULL,		OPTV_NONE,	{0},	FALSE}
 };
 
@@ -257,18 +258,41 @@ static Bool sna_get_early_options(ScrnInfoPtr scrn)
 	return TRUE;
 }
 
+struct sna_device {
+	int fd;
+	int open_count;
+};
+static int sna_device_key;
+
+static inline struct sna_device *sna_device(ScrnInfoPtr scrn)
+{
+	return xf86GetEntityPrivate(scrn->entityList[0], sna_device_key)->ptr;
+}
+
+static inline void sna_set_device(ScrnInfoPtr scrn, struct sna_device *dev)
+{
+	xf86GetEntityPrivate(scrn->entityList[0], sna_device_key)->ptr = dev;
+}
+
 static int sna_open_drm_master(ScrnInfoPtr scrn)
 {
+	struct sna_device *dev;
 	struct sna *sna = to_sna(scrn);
-	struct pci_device *dev = sna->PciInfo;
+	struct pci_device *pci = sna->PciInfo;
 	drmSetVersion sv;
 	struct drm_i915_getparam gp;
 	int err, val;
 	char busid[20];
 	int fd;
 
+	dev = sna_device(scrn);
+	if (dev) {
+		dev->open_count++;
+		return dev->fd;
+	}
+
 	snprintf(busid, sizeof(busid), "pci:%04x:%02x:%02x.%d",
-		 dev->domain, dev->bus, dev->dev, dev->func);
+		 pci->domain, pci->bus, pci->dev, pci->func);
 
 	fd = drmOpen("i915", busid);
 	if (fd == -1) {
@@ -305,15 +329,26 @@ static int sna_open_drm_master(ScrnInfoPtr scrn)
 		return -1;
 	}
 
+	dev = malloc(sizeof(*dev));
+	if (dev) {
+		dev->fd = fd;
+		dev->open_count = 1;
+		sna_set_device(scrn, dev);
+	}
+
 	return fd;
 }
 
-static void sna_close_drm_master(struct sna *sna)
+static void sna_close_drm_master(ScrnInfoPtr scrn)
 {
-	if (sna && sna->kgem.fd > 0) {
-		drmClose(sna->kgem.fd);
-		sna->kgem.fd = -1;
-	}
+	struct sna_device *dev = sna_device(scrn);
+
+	if (--dev->open_count)
+		return;
+
+	drmClose(dev->fd);
+	sna_set_device(scrn, NULL);
+	free(dev);
 }
 
 static void sna_selftest(void)
@@ -321,7 +356,6 @@ static void sna_selftest(void)
 	sna_damage_selftest();
 }
 
-
 /**
  * This is called before ScreenInit to do any require probing of screen
  * configuration.
@@ -811,12 +845,13 @@ static void sna_free_screen(int scrnIndex, int flags)
 
 	if (sna) {
 		sna_mode_fini(sna);
-		sna_close_drm_master(sna);
 
 		free(sna);
 		scrn->driverPrivate = NULL;
 	}
 
+	sna_close_drm_master(scrn);
+
 	if (xf86LoaderCheckSymbol("vgaHWFreeHWRec"))
 		vgaHWFreeHWRec(xf86Screens[scrnIndex]);
 }
@@ -911,8 +946,12 @@ static Bool sna_pm_event(int scrnIndex, pmEvent event, Bool undo)
 	return TRUE;
 }
 
-void sna_init_scrn(ScrnInfoPtr scrn)
+void sna_init_scrn(ScrnInfoPtr scrn, int entity_num)
 {
+	EntityInfoPtr entity;
+
+	sna_device_key = xf86AllocateEntityPrivateIndex();
+
 	scrn->PreInit = sna_pre_init;
 	scrn->ScreenInit = sna_screen_init;
 	scrn->SwitchMode = sna_switch_mode;
@@ -922,4 +961,12 @@ void sna_init_scrn(ScrnInfoPtr scrn)
 	scrn->FreeScreen = sna_free_screen;
 	scrn->ValidMode = sna_valid_mode;
 	scrn->PMEvent = sna_pm_event;
+
+	xf86SetEntitySharable(scrn->entityList[0]);
+
+	entity = xf86GetEntityInfo(entity_num);
+	xf86SetEntityInstanceForScreen(scrn,
+				       entity->index,
+				       xf86GetNumEntityInstances(entity->index)-1);
+	free(entity);
 }

src/sna/sna_module.h

@@ -1,3 +1,3 @@
 const OptionInfoRec *sna_available_options(int chipid, int busid);
-void sna_init_scrn(ScrnInfoPtr scrn);
+void sna_init_scrn(ScrnInfoPtr scrn, int entity_num);