diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index 75afa12..39c0a09 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -650,6 +650,10 @@
 	echo expand_toggle > /proc/acpi/ibm/video
 	echo video_switch > /proc/acpi/ibm/video
 
+NOTE: Access to this feature is restricted to processes owning the
+CAP_SYS_ADMIN capability for safety reasons, as it can interact badly
+enough with some versions of X.org to crash it.
+
 Each video output device can be enabled or disabled individually.
 Reading /proc/acpi/ibm/video shows the status of each device.
 
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index f526e73..11fce79 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -319,9 +319,15 @@
 	  server running, phase of the moon, and the current mood of
 	  Schroedinger's cat.  If you can use X.org's RandR to control
 	  your ThinkPad's video output ports instead of this feature,
-	  don't think twice: do it and say N here to save some memory.
+	  don't think twice: do it and say N here to save memory and avoid
+	  bad interactions with X.org.
 
-	  If you are not sure, say Y here.
+	  NOTE: access to this feature is limited to processes with the
+	  CAP_SYS_ADMIN capability, to avoid local DoS issues in platforms
+	  where it interacts badly with X.org.
+
+	  If you are not sure, say Y here but do try to check if you could
+	  be using X.org RandR instead.
 
 config THINKPAD_ACPI_HOTKEY_POLL
 	bool "Support NVRAM polling for hot keys"
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 3af4628..5d02cc0 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -286,6 +286,7 @@
 	char param[32];
 
 	int (*init) (struct ibm_init_struct *);
+	mode_t base_procfs_mode;
 	struct ibm_struct *data;
 };
 
@@ -4629,6 +4630,10 @@
 		return 0;
 	}
 
+	/* Even reads can crash X.org, so... */
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
 	status = video_outputsw_get();
 	if (status < 0)
 		return status;
@@ -4662,6 +4667,10 @@
 	if (video_supported == TPACPI_VIDEO_NONE)
 		return -ENODEV;
 
+	/* Even reads can crash X.org, let alone writes... */
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
 	enable = 0;
 	disable = 0;
 
@@ -8487,9 +8496,10 @@
 		"%s installed\n", ibm->name);
 
 	if (ibm->read) {
-		mode_t mode;
+		mode_t mode = iibm->base_procfs_mode;
 
-		mode = S_IRUGO;
+		if (!mode)
+			mode = S_IRUGO;
 		if (ibm->write)
 			mode |= S_IWUSR;
 		entry = proc_create_data(ibm->name, mode, proc_dir,
@@ -8680,6 +8690,7 @@
 #ifdef CONFIG_THINKPAD_ACPI_VIDEO
 	{
 		.init = video_init,
+		.base_procfs_mode = S_IRUSR,
 		.data = &video_driver_data,
 	},
 #endif