DRM: add mode setting support

Add mode setting support to the DRM layer.

This is a fairly big chunk of work that allows DRM drivers to provide
full output control and configuration capabilities to userspace.  It was
motivated by several factors:
  - the fb layer's APIs aren't suited for anything but simple
    configurations
  - coordination between the fb layer, DRM layer, and various userspace
    drivers is poor to non-existent (radeonfb excepted)
  - user level mode setting drivers makes displaying panic & oops
    messages more difficult
  - suspend/resume of graphics state is possible in many more
    configurations with kernel level support

This commit just adds the core DRM part of the mode setting APIs.
Driver specific commits using these new structure and APIs will follow.

Co-authors: Jesse Barnes <jbarnes@virtuousgeek.org>, Jakob Bornecrantz <jakob@tungstengraphics.com>
Contributors: Alan Hourihane <alanh@tungstengraphics.com>, Maarten Maathuis <madman2003@gmail.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>

1 files changed, 45 insertions, 19 deletions

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 1e787f894b3c..1608f8dbfda0 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -305,6 +305,8 @@ int drm_control(struct drm_device *dev, void *data,
         case DRM_INST_HANDLER:
                 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                         return 0;
+                if (drm_core_check_feature(dev, DRIVER_MODESET))
+                        return 0;
                 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
                     ctl->irq != dev->pdev->irq)
                         return -EINVAL;
@@ -312,6 +314,8 @@ int drm_control(struct drm_device *dev, void *data,
         case DRM_UNINST_HANDLER:
                 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                         return 0;
+                if (drm_core_check_feature(dev, DRIVER_MODESET))
+                        return 0;
                 return drm_irq_uninstall(dev);
         default:
                 return -EINVAL;
@@ -427,6 +431,45 @@ void drm_vblank_put(struct drm_device *dev, int crtc)
 EXPORT_SYMBOL(drm_vblank_put);
 
 /**
+ * drm_vblank_pre_modeset - account for vblanks across mode sets
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ * @post: post or pre mode set?
+ *
+ * Account for vblank events across mode setting events, which will likely
+ * reset the hardware frame counter.
+ */
+void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
+{
+        /*
+         * To avoid all the problems that might happen if interrupts
+         * were enabled/disabled around or between these calls, we just
+         * have the kernel take a reference on the CRTC (just once though
+         * to avoid corrupting the count if multiple, mismatch calls occur),
+         * so that interrupts remain enabled in the interim.
+         */
+        if (!dev->vblank_inmodeset[crtc]) {
+                dev->vblank_inmodeset[crtc] = 1;
+                drm_vblank_get(dev, crtc);
+        }
+}
+EXPORT_SYMBOL(drm_vblank_pre_modeset);
+
+void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
+{
+        unsigned long irqflags;
+
+        if (dev->vblank_inmodeset[crtc]) {
+                spin_lock_irqsave(&dev->vbl_lock, irqflags);
+                dev->vblank_disable_allowed = 1;
+                dev->vblank_inmodeset[crtc] = 0;
+                spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+                drm_vblank_put(dev, crtc);
+        }
+}
+EXPORT_SYMBOL(drm_vblank_post_modeset);
+
+/**
  * drm_modeset_ctl - handle vblank event counter changes across mode switch
  * @DRM_IOCTL_ARGS: standard ioctl arguments
  *
@@ -441,7 +484,6 @@ int drm_modeset_ctl(struct drm_device *dev, void *data,
                     struct drm_file *file_priv)
 {
         struct drm_modeset_ctl *modeset = data;
-        unsigned long irqflags;
         int crtc, ret = 0;
 
         /* If drm_vblank_init() hasn't been called yet, just no-op */
@@ -454,28 +496,12 @@ int drm_modeset_ctl(struct drm_device *dev, void *data,
                 goto out;
         }
 
-        /*
-         * To avoid all the problems that might happen if interrupts
-         * were enabled/disabled around or between these calls, we just
-         * have the kernel take a reference on the CRTC (just once though
-         * to avoid corrupting the count if multiple, mismatch calls occur),
-         * so that interrupts remain enabled in the interim.
-         */
         switch (modeset->cmd) {
         case _DRM_PRE_MODESET:
-                if (!dev->vblank_inmodeset[crtc]) {
-                        dev->vblank_inmodeset[crtc] = 1;
-                        drm_vblank_get(dev, crtc);
-                }
+                drm_vblank_pre_modeset(dev, crtc);
                 break;
         case _DRM_POST_MODESET:
-                if (dev->vblank_inmodeset[crtc]) {
-                        spin_lock_irqsave(&dev->vbl_lock, irqflags);
-                        dev->vblank_disable_allowed = 1;
-                        dev->vblank_inmodeset[crtc] = 0;
-                        spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
-                        drm_vblank_put(dev, crtc);
-                }
+                drm_vblank_post_modeset(dev, crtc);
                 break;
         default:
                 ret = -EINVAL;