drm/kernel: vblank wait on crtc > 1

Below is a patch against drm-next branch of 2.6.38-rc8+ kernel that adds
the capability to wait on vblank events for CRTCs that are greater than 1
and thus cannot be represented with primary/secondary flags in the legacy
interface. It was discussed on the dri-devel list in these two threads:

http://lists.freedesktop.org/archives/dri-devel/2011-March/009009.html
http://lists.freedesktop.org/archives/dri-devel/2011-March/009025.html

This patch extends the interface to drm_wait_vblank ioctl so that crtc>1
can be represented. It also adds a new capability to drm_getcap ioctl so
that the user space can check whether the new interface to drm_wait_vblank
is supported (and fall back to the legacy interface if not)

Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com>
Reviewed-by: Mario Kleiner <mario.kleiner at tuebingen.mpg.de>
Acked-by: Mario Kleiner <mario.kleiner at tuebingen.mpg.de>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Tested-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

3 files changed, 16 insertions, 5 deletions

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 7f6912a16761..3617b4c4bb57 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -280,6 +280,9 @@ int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
                 if (dev->driver->dumb_create)
                         req->value = 1;
                 break;
+        case DRM_CAP_HIGH_CRTC:
+                req->value = 1;
+                break;
         default:
                 return -EINVAL;
         }
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index a34ef97d3c81..741457bd1c46 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -1125,7 +1125,7 @@ int drm_wait_vblank(struct drm_device *dev, void *data,
 {
         union drm_wait_vblank *vblwait = data;
         int ret = 0;
-        unsigned int flags, seq, crtc;
+        unsigned int flags, seq, crtc, high_crtc;
 
         if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled))
                 return -EINVAL;
@@ -1134,16 +1134,21 @@ int drm_wait_vblank(struct drm_device *dev, void *data,
                 return -EINVAL;
 
         if (vblwait->request.type &
-            ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) {
+            ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
+              _DRM_VBLANK_HIGH_CRTC_MASK)) {
                 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
                           vblwait->request.type,
-                          (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK));
+                          (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
+                           _DRM_VBLANK_HIGH_CRTC_MASK));
                 return -EINVAL;
         }
 
         flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
-        crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
-
+        high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
+        if (high_crtc)
+                crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
+        else
+                crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
         if (crtc >= dev->num_crtcs)
                 return -EINVAL;
 
diff --git a/include/drm/drm.h b/include/drm/drm.h
index 9ac431396176..99cd07433fab 100644
--- a/include/drm/drm.h
+++ b/include/drm/drm.h
@@ -469,6 +469,8 @@ enum drm_vblank_seq_type {
         _DRM_VBLANK_SECONDARY = 0x20000000,     /**< Secondary display controller */
         _DRM_VBLANK_SIGNAL = 0x40000000 /**< Send signal instead of blocking, unsupported */
 };
+#define _DRM_VBLANK_HIGH_CRTC_SHIFT 16
+#define _DRM_VBLANK_HIGH_CRTC_MASK 0x001F0000
 
 #define _DRM_VBLANK_TYPES_MASK (_DRM_VBLANK_ABSOLUTE | _DRM_VBLANK_RELATIVE)
 #define _DRM_VBLANK_FLAGS_MASK (_DRM_VBLANK_EVENT | _DRM_VBLANK_SIGNAL | \
@@ -753,6 +755,7 @@ struct drm_event_vblank {
 };
 
 #define DRM_CAP_DUMB_BUFFER 0x1
+#define DRM_CAP_HIGH_CRTC 0x2
 
 /* typedef area */
 #ifndef __KERNEL__