drm/radeon: add a way to revoke hyper-z access

Signed-off-by: Marek Olšák <maraeo@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 19 insertions, 5 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 948a2f454e42..b1c8ace5f080 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -162,13 +162,27 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
                         return -EINVAL;
                 }
         case RADEON_INFO_WANT_HYPERZ:
+                /* The "value" here is both an input and output parameter.
+                 * If the input value is 1, filp requests hyper-z access.
+                 * If the input value is 0, filp revokes its hyper-z access.
+                 *
+                 * When returning, the value is 1 if filp owns hyper-z access,
+                 * 0 otherwise. */
+                if (value >= 2) {
+                        DRM_DEBUG_KMS("WANT_HYPERZ: invalid value %d\n", value);
+                        return -EINVAL;
+                }
                 mutex_lock(&dev->struct_mutex);
-                if (rdev->hyperz_filp)
-                        value = 0;
-                else {
-                        rdev->hyperz_filp = filp;
-                        value = 1;
+                if (value == 1) {
+                        /* wants hyper-z */
+                        if (!rdev->hyperz_filp)
+                                rdev->hyperz_filp = filp;
+                } else if (value == 0) {
+                        /* revokes hyper-z */
+                        if (rdev->hyperz_filp == filp)
+                                rdev->hyperz_filp = NULL;
                 }
+                value = rdev->hyperz_filp == filp ?  1 : 0;
                 mutex_unlock(&dev->struct_mutex);
                 break;
         default: