drm/i915: Disable all outputs early, before KMS takeover

If the outputs are active and continuing to access the GATT when we
teardown the PTEs, then there is a potential for us to hang the GPU.
The hang tends to be a PGTBL_ER with either an invalid host access or
an invalid display plane fetch.

v2: Reorder IRQ initialisation to defer until after GEM is setup.

Reported-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Daniel Vetter <daniel.vetter@ffwll.ch> (855GM)
Tested-by: Pekka Enberg <penberg@kernel.org>
           # note that this doesn't fix the underlying problem of the
             PGTBL_ER and pipe underruns being reported immediately upon
             init on his 965GM MacBook
Reported-and-tested-by: Rick Bramley <richard.bramley@hp.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=35635
Reported-and-tested-by: Zdenek Kabelac <zdenek.kabelac@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=36048
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>

1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e99ae3bd1064..a38fb3998ad1 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6627,6 +6627,9 @@ static void intel_setup_outputs(struct drm_device *dev)
 	}
 
 	intel_panel_setup_backlight(dev);
+
+	/* disable all the possible outputs/crtcs before entering KMS mode */
+	drm_helper_disable_unused_functions(dev);
 }
 
 static void intel_user_framebuffer_destroy(struct drm_framebuffer *fb)
@@ -7573,13 +7576,12 @@ void intel_modeset_init(struct drm_device *dev)
 		intel_crtc_init(dev, i);
 	}
 
+	/* Just disable it once at startup */
+	i915_disable_vga(dev);
 	intel_setup_outputs(dev);
 
 	intel_enable_clock_gating(dev);
 
-	/* Just disable it once at startup */
-	i915_disable_vga(dev);
-
 	if (IS_IRONLAKE_M(dev)) {
 		ironlake_enable_drps(dev);
 		intel_init_emon(dev);
@@ -7588,12 +7590,15 @@ void intel_modeset_init(struct drm_device *dev)
 	if (IS_GEN6(dev))
 		gen6_enable_rps(dev_priv);
 
-	if (IS_IRONLAKE_M(dev))
-		ironlake_enable_rc6(dev);
-
 	INIT_WORK(&dev_priv->idle_work, intel_idle_update);
 	setup_timer(&dev_priv->idle_timer, intel_gpu_idle_timer,
 		    (unsigned long)dev);
+}
+
+void intel_modeset_gem_init(struct drm_device *dev)
+{
+	if (IS_IRONLAKE_M(dev))
+		ironlake_enable_rc6(dev);
 
 	intel_setup_overlay(dev);
 }