Index: xserver-xorg-video-intel-2.19.0/src/intel_display.c
===================================================================
--- xserver-xorg-video-intel-2.19.0.orig/src/intel_display.c	2012-07-07 21:15:02.000000000 +0300
+++ xserver-xorg-video-intel-2.19.0/src/intel_display.c	2012-07-07 21:19:25.000000000 +0300
@@ -121,7 +121,8 @@
 #define BACKLIGHT_CLASS "/sys/class/backlight"
 
 /*
- * List of available kernel interfaces in priority order
+ * List of available kernel interfaces in priority order.
+ * May be overridden by a model-specific workaround.
  */
 static const char *backlight_interfaces[] = {
 	"asus-laptop",
@@ -243,28 +244,126 @@
 	return max;
 }
 
+static Bool
+intel_output_backlight_probe(xf86OutputPtr output, const char *iface)
+{
+	struct intel_output *intel_output = output->driver_private;
+	char path[BACKLIGHT_PATH_LEN];
+	struct stat buf;
+
+	sprintf(path, "%s/%s", BACKLIGHT_CLASS, iface);
+	if (!stat(path, &buf)) {
+		intel_output->backlight_iface = iface;
+		intel_output->backlight_max = intel_output_backlight_get_max(output);
+		if (intel_output->backlight_max > 0) {
+			intel_output->backlight_active_level = intel_output_backlight_get(output);
+			xf86DrvMsg(output->scrn->scrnIndex, X_INFO,
+				   "found backlight control interface %s\n", path);
+			return TRUE;
+		}
+	}
+
+	return FALSE;
+}
+
+static Bool
+intel_output_dmi_match(xf86OutputPtr output, const char *pathname,
+		       const char *expect)
+{
+	/* This buffer is large enough for the strings we recognize.
+	 * Longer strings will be truncated.  */
+	char buf[50];
+	int fd;
+	ssize_t size;
+	Bool match = FALSE;
+
+	fd = open(pathname, O_RDONLY);
+	if (fd != -1) {
+		/* Leave room for '\0'.  */
+		size = read(fd, buf, sizeof(buf) - 1);
+		if (size != -1) {
+			/* Remove trailing newlines and spaces.  */
+			while (size > 0 && (buf[size - 1] == '\n'
+					    || buf[size - 1] == ' '))
+				--size;
+
+			buf[size] = '\0';
+			xf86DrvMsg(output->scrn->scrnIndex, X_INFO,
+				   "DMI ID in %s: %s\n", pathname, buf);
+			if (strcmp(buf, expect) == 0)
+				match = TRUE;
+		}
+		close(fd);
+	}
+
+	return match;
+}
+
+static Bool
+intel_output_prefer_intel_backlight(xf86OutputPtr output)
+{
+	intel_screen_private *intel = intel_get_screen_private(output->scrn);
+
+	/* With Linux 3.1.0 on Sony VAIO VPCYA1V9E, both acpi_video0
+	 * and intel_backlight exist and can be adjusted, but only
+	 * intel_backlight affects the display.  Reported at:
+	 * - http://bugs.debian.org/651741
+	 * - https://bugs.freedesktop.org/show_bug.cgi?id=44809
+	 * DMI information:
+	 * - bios_date: 11/02/2010
+	 * - bios_vendor: INSYDE
+	 * - bios_version: R0070Z6
+	 * - board_name: VAIO
+	 * - board_vendor: Sony Corporation
+	 * - board_version: N/A
+	 * - chassis_type: 10
+	 * - chassis_vendor: Sony Corporation
+	 * - chassis_version: N/A
+	 * - product_name: VPCYA1V9E
+	 * - product_version: C9006WUT
+	 * - sys_vendor: Sony Corporation
+	 */
+	if (VENDOR_ID(intel->PciInfo) == 0x8086 /* Intel */
+	    && DEVICE_ID(intel->PciInfo) == PCI_CHIP_IRONLAKE_M_G
+	    && CHIP_REVISION(intel->PciInfo) == 0x02
+	    && SUBVENDOR_ID(intel->PciInfo) == 0x104d /* Sony */
+	    && SUBSYS_ID(intel->PciInfo) == 0x907c
+	    && intel_output_dmi_match(output, "/sys/class/dmi/id/sys_vendor", "Sony Corporation")
+	    && intel_output_dmi_match(output, "/sys/class/dmi/id/product_name", "VPCYA1V9E")
+	    && intel_output_dmi_match(output, "/sys/class/dmi/id/product_version", "C9006WUT"))
+		return TRUE;
+
+	if (VENDOR_ID(intel->PciInfo) == 0x8086 /* Intel */
+	    && DEVICE_ID(intel->PciInfo) == PCI_CHIP_IRONLAKE_M_G
+	    && CHIP_REVISION(intel->PciInfo) == 0x18
+	    && SUBVENDOR_ID(intel->PciInfo) == 0x17aa /* Lenovo */
+	    && SUBSYS_ID(intel->PciInfo) == 0x3920
+	    && intel_output_dmi_match(output, "/sys/class/dmi/id/sys_vendor", "LENOVO")
+	    && intel_output_dmi_match(output, "/sys/class/dmi/id/product_name", "G360")
+	    && intel_output_dmi_match(output, "/sys/class/dmi/id/product_version", "Rev 1.0"))
+		return TRUE;
+
+	return FALSE;
+}
+
 static void
 intel_output_backlight_init(xf86OutputPtr output)
 {
 	struct intel_output *intel_output = output->driver_private;
 	int i;
 
-	for (i = 0; backlight_interfaces[i] != NULL; i++) {
-		char path[BACKLIGHT_PATH_LEN];
-		struct stat buf;
+	if (intel_output_prefer_intel_backlight(output)) {
+		xf86DrvMsg(output->scrn->scrnIndex, X_INFO,
+			   "will prefer intel_backlight on this computer\n");
+		if (intel_output_backlight_probe(output, "intel_backlight"))
+			return;
+	}
 
-		sprintf(path, "%s/%s", BACKLIGHT_CLASS, backlight_interfaces[i]);
-		if (!stat(path, &buf)) {
-			intel_output->backlight_iface = backlight_interfaces[i];
-			intel_output->backlight_max = intel_output_backlight_get_max(output);
-			if (intel_output->backlight_max > 0) {
-				intel_output->backlight_active_level = intel_output_backlight_get(output);
-				xf86DrvMsg(output->scrn->scrnIndex, X_INFO,
-					   "found backlight control interface %s\n", path);
-				return;
-			}
-		}
+	for (i = 0; backlight_interfaces[i] != NULL; i++) {
+		if (intel_output_backlight_probe(output, backlight_interfaces[i]))
+			return;
 	}
+
 	intel_output->backlight_iface = NULL;
 }