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

[Michel Dänzer]

From: Michel Dänzer <michel.daen...@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