[PATCH] drm/i915: fix plane/cursor handling when runtime suspended

Paulo Zanoni
2014-08-12T18:55:30Z

From: Paulo Zanoni <paulo.r.zanoni@intel.com>

If we're runtime suspended and try to use the plane interfaces, we
will get a lot of WARNs saying we did the wrong thing.

We need to get runtime PM references to pin/unpin the objects, and to
change the fences. The pin/unpin functions are the ideal places for
this, but intel_crtc_cursor_set_obj() doesn't call them, so we also
have to add get/put calls inside it. There is no problem if we runtime
suspend right after these functions are finished, because the
registers written are forwarded to system memory.

Note: for a complete fix of the cursor-dpms test case, we also need
the patch named "drm/i915: Don't try to enable cursor from setplane
when crtc is disabled".

v2: - Narrow the put/get calls on intel_crtc_cursor_set_obj() (Daniel)
v3: - Make get/put also surround the fence and unpin calls (Daniel and
Ville).
- Merge all the plane changes into a single patch since they're
the same fix.
- Add the comment requested by Daniel.
v4: - Remove spurious whitespace (Ville).
v5: - Remove intel_crtc_update_cursor() chunk since Ville did an
equivalent fix in another patch (Ville).

Testcase: igt/pm_rpm/cursor
Testcase: igt/pm_rpm/cursor-dpms
Testcase: igt/pm_rpm/legacy-planes
Testcase: igt/pm_rpm/legacy-planes-dpms
Testcase: igt/pm_rpm/universal-planes
Testcase: igt/pm_rpm/universal-planes-dpms
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=81645
Cc: stable@vger.kernel.org
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a1cf052..2db9e06 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2149,6 +2149,15 @@ intel_pin_and_fence_fb_obj(struct drm_device *dev,
if (need_vtd_wa(dev) && alignment < 256 * 1024)
alignment = 256 * 1024;

+ /*
+ * Global gtt pte registers are special registers which actually forward
+ * writes to a chunk of system memory. Which means that there is no risk
+ * that the register values disappear as soon as we call
+ * intel_runtime_pm_put(), so it is correct to wrap only the
+ * pin/unpin/fence and not more.
+ */
+ intel_runtime_pm_get(dev_priv);
+
dev_priv->mm.interruptible = false;
ret = i915_gem_object_pin_to_display_plane(obj, alignment, pipelined);
if (ret)
@@ -2166,21 +2175,30 @@ intel_pin_and_fence_fb_obj(struct drm_device *dev,
i915_gem_object_pin_fence(obj);

dev_priv->mm.interruptible = true;
+ intel_runtime_pm_put(dev_priv);
return 0;

err_unpin:
i915_gem_object_unpin_from_display_plane(obj);
err_interruptible:
dev_priv->mm.interruptible = true;
+ intel_runtime_pm_put(dev_priv);
return ret;
}

void intel_unpin_fb_obj(struct drm_i915_gem_object *obj)
{
- WARN_ON(!mutex_is_locked(&obj->base.dev->struct_mutex));
+ struct drm_device *dev = obj->base.dev;
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+
+ intel_runtime_pm_get(dev_priv);

i915_gem_object_unpin_fence(obj);
i915_gem_object_unpin_from_display_plane(obj);
+
+ intel_runtime_pm_put(dev_priv);
}

/* Computes the linear offset to the base tile and adjusts x, y. bytes per pixel
@@ -8170,6 +8188,16 @@ static int intel_crtc_cursor_set_obj(struct drm_crtc *crtc,

/* we only need to pin inside GTT if cursor is non-phy */
mutex_lock(&dev->struct_mutex);
+
+ /*
+ * Global gtt pte registers are special registers which actually forward
+ * writes to a chunk of system memory. Which means that there is no risk
+ * that the register values disappear as soon as we call
+ * intel_runtime_pm_put(), so it is correct to wrap only the
+ * pin/unpin/fence and not more.
+ */
+ intel_runtime_pm_get(dev_priv);
+
if (!INTEL_INFO(dev)->cursor_needs_physical) {
unsigned alignment;

@@ -8219,6 +8247,10 @@ static int intel_crtc_cursor_set_obj(struct drm_crtc *crtc,

i915_gem_track_fb(intel_crtc->cursor_bo, obj,
INTEL_FRONTBUFFER_CURSOR(pipe));
+
+ if (obj)
+ intel_runtime_pm_put(dev_priv);
+
mutex_unlock(&dev->struct_mutex);

old_width = intel_crtc->cursor_width;
@@ -8240,6 +8272,7 @@ static int intel_crtc_cursor_set_obj(struct drm_crtc *crtc,
fail_unpin:
i915_gem_object_unpin_from_display_plane(obj);
fail_locked:
+ intel_runtime_pm_put(dev_priv);
mutex_unlock(&dev->struct_mutex);
fail:
drm_gem_object_unreference_unlocked(&obj->base);
--
2.0.1