drm/i915: Enable atomic support by default on supported platforms.

i915 is pretty much feature complete. Support for atomic i915-specific
connector properties is still missing; those properties can (for now)
only be set through the legacy ioctl.

ILK style watermarks and gen9+ watermarks are handled atomically,
and nonblocking modesets work. FBC has also been made to work with
atomic.

gen4x- and vlv/chv watermarks still need to be fixed, so disable atomic
by default there for now.

Flip the switch!!

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Lyude <cpaul@redhat.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1486021302-24910-1-git-send-email-maarten.lankhorst@linux.intel.com
[mlankhorst: Fix checkpatch warning about extra space in match_info]
Acked-by: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Lyude <lyude@redhat.com>

drivers/gpu/drm/i915/i915_drv.c

@@ -1214,11 +1214,15 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv)
  */
 int i915_driver_load(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
+	const struct intel_device_info *match_info =
+		(struct intel_device_info *)ent->driver_data;
 	struct drm_i915_private *dev_priv;
 	int ret;
 
-	if (i915.nuclear_pageflip)
-		driver.driver_features |= DRIVER_ATOMIC;
+	/* Enable nuclear pageflip on ILK+, except vlv/chv */
+	if (!i915.nuclear_pageflip &&
+	    (match_info->gen < 5 || match_info->has_gmch_display))
+		driver.driver_features &= ~DRIVER_ATOMIC;
 
 	ret = -ENOMEM;
 	dev_priv = kzalloc(sizeof(*dev_priv), GFP_KERNEL);
@@ -2624,7 +2628,7 @@ static struct drm_driver driver = {
 	 */
 	.driver_features =
 	    DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_GEM | DRIVER_PRIME |
-	    DRIVER_RENDER | DRIVER_MODESET,
+	    DRIVER_RENDER | DRIVER_MODESET | DRIVER_ATOMIC,
 	.open = i915_driver_open,
 	.lastclose = i915_driver_lastclose,
 	.preclose = i915_driver_preclose,

drivers/gpu/drm/i915/i915_params.c

@@ -205,9 +205,9 @@ module_param_named(verbose_state_checks, i915.verbose_state_checks, bool, 0600);
 MODULE_PARM_DESC(verbose_state_checks,
 	"Enable verbose logs (ie. WARN_ON()) in case of unexpected hw state conditions.");
 
-module_param_named_unsafe(nuclear_pageflip, i915.nuclear_pageflip, bool, 0600);
+module_param_named_unsafe(nuclear_pageflip, i915.nuclear_pageflip, bool, 0400);
 MODULE_PARM_DESC(nuclear_pageflip,
-		 "Force atomic modeset functionality; asynchronous mode is not yet supported. (default: false).");
+		 "Force enable atomic functionality on platforms that don't have full support yet.");
 
 /* WA to get away with the default setting in VBT for early platforms.Will be removed */
 module_param_named_unsafe(edp_vswing, i915.edp_vswing, int, 0400);