drm/i915: Hold runtime PM during plane commit

mattrope · danvet · commit 140fd38dc496 · 2014-12-17T21:32:59.000+01:00
During plane operations, we read/write some registers that only operate properly if we're not runtime suspended. At the moment we're not holding the runtime PM reference across the whole plane operation, so there's a potential for problems. This issue was already partially addressed by commit commit d6dd684 Author: Paulo Zanoni <paulo.r.zanoni@intel.com> Date: Fri Aug 15 15:59:32 2014 -0300 drm/i915: fix plane/cursor handling when runtime suspended which took care of holding the runtime PM reference during the pin and fence operations for plane updates. However there are still a few actual plane registers that we also need to hold the runtime PM reference for. Recent refactoring patches in preparation for atomic have rearranged the code and made it increasingly likely that the hardware will have time to suspend between the pin/fence operation and the actual register writes. Examples of such registers are the stuff touched by ivb_get_colorkey. The solution here grabs the runtime PM reference around the 'commit' operation for planes, which should cover all the relevant register reads/writes. Note that this has only been exposed with commit 6beb8c2 Author: Matt Roper <matthew.d.roper@intel.com> Date: Mon Dec 1 15:40:14 2014 -0800 drm/i915: Consolidate plane 'prepare' functions (v2) so doesn't need to be ported to 3.19. Cc: Paulo Zanoni <paulo.r.zanoni@intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=87180 Signed-off-by: Matt Roper <matthew.d.roper@intel.com> Testcase: igt/pm-rpm/legacy-planes Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com> [danvet: Augment commit message with information Paulo supplied.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
@@ -11864,6 +11864,7 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		   uint32_t src_w, uint32_t src_h)
 {
 	struct drm_device *dev = plane->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_framebuffer *old_fb = plane->fb;
 	struct intel_plane_state state;
 	struct intel_plane *intel_plane = to_intel_plane(plane);
@@ -11903,7 +11904,9 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 			return ret;
 	}
 
+	intel_runtime_pm_get(dev_priv);
 	intel_plane->commit_plane(plane, &state);
+	intel_runtime_pm_put(dev_priv);
 
 	if (fb != old_fb && old_fb) {
 		if (intel_crtc->active)
