[Intel-gfx] [PATCH 1/2] drm/i915: Disallow pin ioctl completely for kms drivers

[Daniel Vetter]

The problem here is that SNA pins batchbuffers to etch out a bit more
performance. Iirc it started out as a w/a for i830M (which we've
implemented in the kernel since a long time already). The problem is
that the pin ioctl wasn't added in

commit d23db88c3ab233daed18709e3a24d6c95344117f
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Fri May 23 08:48:08 2014 +0200

    drm/i915: Prevent negative relocation deltas from wrapping

Fix this by simply disallowing pinning from userspace so that the
kernel is in full control of batch placement again. Especially since
distros are moving towards running X as non-root, so most users won't
even be able to see any benefits.

UMS support is dead now, but we need this minimal patch for
backporting. Follow-up patch will remove the pin ioctl code
completely.

References: https://bugs.freedesktop.org/show_bug.cgi?id=76554#c116
Cc: stable at vger.kernel.org
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 3c64eb6abf2d..fb5ce2b89aba 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4245,7 +4245,7 @@ i915_gem_pin_ioctl(struct drm_device *dev, void *data,
 	struct drm_i915_gem_object *obj;
 	int ret;
 
-	if (INTEL_INFO(dev)->gen >= 6)
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
 		return -ENODEV;
 
 	ret = i915_mutex_lock_interruptible(dev);
@@ -4301,6 +4301,9 @@ i915_gem_unpin_ioctl(struct drm_device *dev, void *data,
 	struct drm_i915_gem_object *obj;
 	int ret;
 
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		return -ENODEV;
+
 	ret = i915_mutex_lock_interruptible(dev);
 	if (ret)
 		return ret;
-- 
2.1.1