drm/vc4: Add a getparam to signal support for branches.

Userspace needs to know if it can create shaders that do branching.
Otherwise, for backwards compatibility with old kernels it needs to
lower if statements to conditional assignments.

Signed-off-by: Eric Anholt <eric@anholt.net>

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 047d7a265ceb77094f501bece5f70abcae5a9202..9435894822d56f4f42bf0036e022b69865caf730 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -76,6 +76,9 @@ static int vc4_get_param_ioctl(struct drm_device *dev, void *data,
                args->value = V3D_READ(V3D_IDENT2);
                pm_runtime_put(&vc4->v3d->pdev->dev);
                break;
+       case DRM_VC4_PARAM_SUPPORTS_BRANCHES:
+               args->value = true;
+               break;
        default:
                DRM_DEBUG("Unknown parameter %d\n", args->param);
                return -EINVAL;

diff --git a/include/uapi/drm/vc4_drm.h b/include/uapi/drm/vc4_drm.h
index 1143e954048d1f8192142361315531066c9ac9af..ad7edc3edf7ca1d653a0bc025a5eda6692b74370 100644 (file)
--- a/include/uapi/drm/vc4_drm.h
+++ b/include/uapi/drm/vc4_drm.h
@@ -285,6 +285,7 @@ struct drm_vc4_get_hang_state {
 #define DRM_VC4_PARAM_V3D_IDENT0               0
 #define DRM_VC4_PARAM_V3D_IDENT1               1
 #define DRM_VC4_PARAM_V3D_IDENT2               2
+#define DRM_VC4_PARAM_SUPPORTS_BRANCHES                3
 
 struct drm_vc4_get_param {
        __u32 param;