radeon: Try harder to ensure we reclock in vblank

The vblank interrupt on r600 doesn't seem to be especially reliable, so
perform some sanity checks before the actual reclock.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/r500_reg.h

@@ -351,6 +351,7 @@
 #define AVIVO_D1CRTC_BLANK_CONTROL                              0x6084
 #define AVIVO_D1CRTC_INTERLACE_CONTROL                          0x6088
 #define AVIVO_D1CRTC_INTERLACE_STATUS                           0x608c
+#define AVIVO_D1CRTC_STATUS_POSITION                            0x60a0
 #define AVIVO_D1CRTC_FRAME_COUNT                                0x60a4
 #define AVIVO_D1CRTC_STEREO_CONTROL                             0x60c4
 
@@ -489,6 +490,7 @@
 #define AVIVO_D2CRTC_BLANK_CONTROL                              0x6884
 #define AVIVO_D2CRTC_INTERLACE_CONTROL                          0x6888
 #define AVIVO_D2CRTC_INTERLACE_STATUS                           0x688c
+#define AVIVO_D2CRTC_STATUS_POSITION                            0x68a0
 #define AVIVO_D2CRTC_FRAME_COUNT                                0x68a4
 #define AVIVO_D2CRTC_STEREO_CONTROL                             0x68c4
 

drivers/gpu/drm/radeon/r600.c

@@ -289,8 +289,34 @@ void r600_set_power_state(struct radeon_device *rdev, bool static_switch)
 			}
 
 		} else {
+			u32 position;
+			u32 vbl;
+
 			radeon_sync_with_vblank(rdev);
 
+			if (!radeon_pm_in_vbl(rdev))
+				return;
+
+			if (rdev->pm.active_crtcs & (1 << 0)) {
+				vbl = RREG32(AVIVO_D1CRTC_V_BLANK_START_END);
+				position = RREG32(AVIVO_D1CRTC_STATUS_POSITION);
+				position &= 0xfff;
+				vbl &= 0xfff;
+
+				if (position < vbl && position > 1)
+					return;
+			}
+
+			if (rdev->pm.active_crtcs & (1 << 1)) {
+				vbl = RREG32(AVIVO_D2CRTC_V_BLANK_START_END);
+				position = RREG32(AVIVO_D2CRTC_STATUS_POSITION);
+				position &= 0xfff;
+				vbl &= 0xfff;
+
+				if (position < vbl && position > 1)
+					return;
+			}
+
 			if (sclk != rdev->pm.current_sclk) {
 				radeon_pm_debug_check_in_vbl(rdev, false);
 				radeon_set_engine_clock(rdev, sclk);

drivers/gpu/drm/radeon/radeon.h

@@ -175,6 +175,7 @@ void radeon_pm_fini(struct radeon_device *rdev);
 void radeon_pm_compute_clocks(struct radeon_device *rdev);
 void radeon_combios_get_power_modes(struct radeon_device *rdev);
 void radeon_atombios_get_power_modes(struct radeon_device *rdev);
+bool radeon_pm_in_vbl(struct radeon_device *rdev);
 bool radeon_pm_debug_check_in_vbl(struct radeon_device *rdev, bool finish);
 void radeon_sync_with_vblank(struct radeon_device *rdev);
 

drivers/gpu/drm/radeon/radeon_pm.c

@@ -387,7 +387,7 @@ void radeon_pm_compute_clocks(struct radeon_device *rdev)
 	mutex_unlock(&rdev->pm.mutex);
 }
 
-bool radeon_pm_debug_check_in_vbl(struct radeon_device *rdev, bool finish)
+bool radeon_pm_in_vbl(struct radeon_device *rdev)
 {
 	u32 stat_crtc = 0;
 	bool in_vbl = true;
@@ -446,6 +446,15 @@ bool radeon_pm_debug_check_in_vbl(struct radeon_device *rdev, bool finish)
 				in_vbl = false;
 		}
 	}
+
+	return in_vbl;
+}
+
+bool radeon_pm_debug_check_in_vbl(struct radeon_device *rdev, bool finish)
+{
+	u32 stat_crtc = 0;
+	bool in_vbl = radeon_pm_in_vbl(rdev);
+
 	if (in_vbl == false)
 		DRM_INFO("not in vbl for pm change %08x at %s\n", stat_crtc,
 			 finish ? "exit" : "entry");