ACPI: Populate DIDL before registering ACPI video device on Intel

Intel graphics hardware that implements the ACPI IGD OpRegion spec
requires that the list of display devices be populated before any ACPI
video methods are called. Detect when this is the case and defer
registration until the opregion code calls it. Fixes crashes on HP
laptops.

http://bugzilla.kernel.org/show_bug.cgi?id=11259

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/video.c

@@ -37,6 +37,8 @@
 #include <linux/thermal.h>
 #include <linux/video_output.h>
 #include <linux/sort.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
 #include <asm/uaccess.h>
 
 #include <acpi/acpi_bus.h>
@@ -2251,7 +2253,27 @@ static int acpi_video_bus_remove(struct acpi_device *device, int type)
 	return 0;
 }
 
-static int __init acpi_video_init(void)
+static int __init intel_opregion_present(void)
+{
+#if defined(CONFIG_DRM_I915) || defined(CONFIG_DRM_I915_MODULE)
+	struct pci_dev *dev = NULL;
+	u32 address;
+
+	for_each_pci_dev(dev) {
+		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
+			continue;
+		if (dev->vendor != PCI_VENDOR_ID_INTEL)
+			continue;
+		pci_read_config_dword(dev, 0xfc, &address);
+		if (!address)
+			continue;
+		return 1;
+	}
+#endif
+	return 0;
+}
+
+int acpi_video_register(void)
 {
 	int result = 0;
 
@@ -2268,6 +2290,22 @@ static int __init acpi_video_init(void)
 
 	return 0;
 }
+EXPORT_SYMBOL(acpi_video_register);
+
+/*
+ * This is kind of nasty. Hardware using Intel chipsets may require
+ * the video opregion code to be run first in order to initialise
+ * state before any ACPI video calls are made. To handle this we defer
+ * registration of the video class until the opregion code has run.
+ */
+
+static int __init acpi_video_init(void)
+{
+	if (intel_opregion_present())
+		return 0;
+
+	return acpi_video_register();
+}
 
 static void __exit acpi_video_exit(void)
 {

drivers/gpu/drm/i915/i915_dma.c

@@ -1144,8 +1144,6 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	if (!IS_I945G(dev) && !IS_I945GM(dev))
 		pci_enable_msi(dev->pdev);
 
-	intel_opregion_init(dev);
-
 	spin_lock_init(&dev_priv->user_irq_lock);
 	dev_priv->user_irq_refcount = 0;
 
@@ -1164,6 +1162,9 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 		}
 	}
 
+	/* Must be done after probing outputs */
+	intel_opregion_init(dev, 0);
+
 	return 0;
 
 out_iomapfree:

drivers/gpu/drm/i915/i915_drv.c

@@ -99,7 +99,7 @@ static int i915_resume(struct drm_device *dev)
 
 	i915_restore_state(dev);
 
-	intel_opregion_init(dev);
+	intel_opregion_init(dev, 1);
 
 	/* KMS EnterVT equivalent */
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {

drivers/gpu/drm/i915/i915_drv.h

@@ -659,7 +659,7 @@ extern int i915_restore_state(struct drm_device *dev);
 
 #ifdef CONFIG_ACPI
 /* i915_opregion.c */
-extern int intel_opregion_init(struct drm_device *dev);
+extern int intel_opregion_init(struct drm_device *dev, int resume);
 extern void intel_opregion_free(struct drm_device *dev);
 extern void opregion_asle_intr(struct drm_device *dev);
 extern void opregion_enable_asle(struct drm_device *dev);

drivers/gpu/drm/i915/i915_opregion.c

@@ -26,6 +26,7 @@
  */
 
 #include <linux/acpi.h>
+#include <acpi/video.h>
 
 #include "drmP.h"
 #include "i915_drm.h"
@@ -136,6 +137,12 @@ struct opregion_asle {
 
 #define ASLE_CBLV_VALID         (1<<31)
 
+#define ACPI_OTHER_OUTPUT (0<<8)
+#define ACPI_VGA_OUTPUT (1<<8)
+#define ACPI_TV_OUTPUT (2<<8)
+#define ACPI_DIGITAL_OUTPUT (3<<8)
+#define ACPI_LVDS_OUTPUT (4<<8)
+
 static u32 asle_set_backlight(struct drm_device *dev, u32 bclp)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -282,7 +289,58 @@ static struct notifier_block intel_opregion_notifier = {
 	.notifier_call = intel_opregion_video_event,
 };
 
-int intel_opregion_init(struct drm_device *dev)
+/*
+ * Initialise the DIDL field in opregion. This passes a list of devices to
+ * the firmware. Values are defined by section B.4.2 of the ACPI specification
+ * (version 3)
+ */
+
+static void intel_didl_outputs(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_opregion *opregion = &dev_priv->opregion;
+	struct drm_connector *connector;
+	int i = 0;
+
+	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+		int output_type = ACPI_OTHER_OUTPUT;
+		if (i >= 8) {
+			dev_printk (KERN_ERR, &dev->pdev->dev,
+				    "More than 8 outputs detected\n");
+			return;
+		}
+		switch (connector->connector_type) {
+		case DRM_MODE_CONNECTOR_VGA:
+		case DRM_MODE_CONNECTOR_DVIA:
+			output_type = ACPI_VGA_OUTPUT;
+			break;
+		case DRM_MODE_CONNECTOR_Composite:
+		case DRM_MODE_CONNECTOR_SVIDEO:
+		case DRM_MODE_CONNECTOR_Component:
+		case DRM_MODE_CONNECTOR_9PinDIN:
+			output_type = ACPI_TV_OUTPUT;
+			break;
+		case DRM_MODE_CONNECTOR_DVII:
+		case DRM_MODE_CONNECTOR_DVID:
+		case DRM_MODE_CONNECTOR_DisplayPort:
+		case DRM_MODE_CONNECTOR_HDMIA:
+		case DRM_MODE_CONNECTOR_HDMIB:
+			output_type = ACPI_DIGITAL_OUTPUT;
+			break;
+		case DRM_MODE_CONNECTOR_LVDS:
+			output_type = ACPI_LVDS_OUTPUT;
+			break;
+		}
+		opregion->acpi->didl[i] |= (1<<31) | output_type | i;
+		i++;
+	}
+
+	/* If fewer than 8 outputs, the list must be null terminated */
+	if (i < 8)
+		opregion->acpi->didl[i] = 0;
+}
+
+int intel_opregion_init(struct drm_device *dev, int resume)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_opregion *opregion = &dev_priv->opregion;
@@ -312,6 +370,11 @@ int intel_opregion_init(struct drm_device *dev)
 	if (mboxes & MBOX_ACPI) {
 		DRM_DEBUG("Public ACPI methods supported\n");
 		opregion->acpi = base + OPREGION_ACPI_OFFSET;
+		if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+			intel_didl_outputs(dev);
+			if (!resume)
+				acpi_video_register();
+		}
 	} else {
 		DRM_DEBUG("Public ACPI methods not supported\n");
 		err = -ENOTSUPP;

include/acpi/video.h

@@ -0,0 +1,11 @@
+#ifndef __ACPI_VIDEO_H
+#define __ACPI_VIDEO_H
+
+#if (defined CONFIG_ACPI_VIDEO || defined CONFIG_ACPI_VIDEO_MODULE)
+extern int acpi_video_register(void);
+#else
+static inline int acpi_video_register(void) { return 0; }
+#endif
+
+#endif
+