[PATCH 2/2] drm: Return -ENOTSUPP when called for KMS cap with a non-KMS driver

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

This is an attempt to make the previous fix a bit more robust going
forward.

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 drivers/gpu/drm/drm_ioctl.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 71c3473..32f484b 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -229,6 +229,19 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 	struct drm_crtc *crtc;
 
 	req->value = 0;
+
+	/* Only allow non-KMS caps with non-KMS drivers */
+	switch (req->capability) {
+	case DRM_CAP_DUMB_BUFFER:
+	case DRM_CAP_VBLANK_HIGH_CRTC:
+	case DRM_CAP_PRIME:
+	case DRM_CAP_TIMESTAMP_MONOTONIC:
+		break;
+	default:
+		if (!drm_core_check_feature(dev, DRIVER_MODESET))
+			return -ENOTSUPP;
+	}
+
 	switch (req->capability) {
 	case DRM_CAP_DUMB_BUFFER:
 		if (dev->driver->dumb_create)
@@ -254,12 +267,10 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 		req->value = dev->mode_config.async_page_flip;
 		break;
 	case DRM_CAP_PAGE_FLIP_TARGET:
-		if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-			req->value = 1;
-			drm_for_each_crtc(crtc, dev) {
-				if (!crtc->funcs->page_flip_target)
-					req->value = 0;
-			}
+		req->value = 1;
+		drm_for_each_crtc(crtc, dev) {
+			if (!crtc->funcs->page_flip_target)
+				req->value = 0;
 		}
 		break;
 	case DRM_CAP_CURSOR_WIDTH:
-- 
2.10.2