DRM: i915: add mode setting support

This commit adds i915 driver support for the DRM mode setting APIs.
Currently, VGA, LVDS, SDVO DVI & VGA, TV and DVO LVDS outputs are
supported.  HDMI, DisplayPort and additional SDVO output support will
follow.

Support for the mode setting code is controlled by the new 'modeset'
module option.  A new config option, CONFIG_DRM_I915_KMS controls the
default behavior, and whether a PCI ID list is built into the module for
use by user level module utilities.

Note that if mode setting is enabled, user level drivers that access
display registers directly or that don't use the kernel graphics memory
manager will likely corrupt kernel graphics memory, disrupt output
configuration (possibly leading to hangs and/or blank displays), and
prevent panic/oops messages from appearing.  So use caution when
enabling this code; be sure your user level code supports the new
interfaces.

A new SysRq key, 'g', provides emergency support for switching back to
the kernel's framebuffer console; which is useful for testing.

Co-authors: Dave Airlie <airlied@linux.ie>, Hong Liu <hong.liu@intel.com>

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 9b673d2..0cadafb 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -30,6 +30,7 @@
 #include "drm.h"
 #include "i915_drm.h"
 #include "i915_drv.h"
+#include "intel_drv.h"
 
 #define MAX_NOPID ((u32)~0)
 
@@ -51,6 +52,15 @@
 #define I915_INTERRUPT_ENABLE_MASK (I915_INTERRUPT_ENABLE_FIX | \
 				    I915_INTERRUPT_ENABLE_VAR)
 
+#define I915_PIPE_VBLANK_STATUS	(PIPE_START_VBLANK_INTERRUPT_STATUS |\
+				 PIPE_VBLANK_INTERRUPT_STATUS)
+
+#define I915_PIPE_VBLANK_ENABLE	(PIPE_START_VBLANK_INTERRUPT_ENABLE |\
+				 PIPE_VBLANK_INTERRUPT_ENABLE)
+
+#define DRM_I915_VBLANK_PIPE_ALL	(DRM_I915_VBLANK_PIPE_A | \
+					 DRM_I915_VBLANK_PIPE_B)
+
 void
 i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
 {
@@ -201,6 +211,7 @@
 		spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
 		pipea_stats = I915_READ(PIPEASTAT);
 		pipeb_stats = I915_READ(PIPEBSTAT);
+
 		/*
 		 * Clear the PIPE(A|B)STAT regs before the IIR
 		 */
@@ -427,6 +438,14 @@
 	spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
 }
 
+void i915_enable_interrupt (struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	opregion_enable_asle(dev);
+	dev_priv->irq_enabled = 1;
+}
+
+
 /* Set the vblank monitor pipe
  */
 int i915_vblank_pipe_set(struct drm_device *dev, void *data,
@@ -487,6 +506,8 @@
 {
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 
+	atomic_set(&dev_priv->irq_received, 0);
+
 	I915_WRITE(HWSTAM, 0xeffe);
 	I915_WRITE(PIPEASTAT, 0);
 	I915_WRITE(PIPEBSTAT, 0);