drm/radeon: use status regs to determine what to reset (cayman)

When we attempt the reset the GPU, look at the status registers
to determine what blocks need to be reset.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index 8b73743..fd5e002 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -2349,9 +2349,13 @@
 		RREG32(CP_STAT));
 	dev_info(rdev->dev, "  R_00D034_DMA_STATUS_REG   = 0x%08X\n",
 		RREG32(DMA_STATUS_REG));
+	if (rdev->family >= CHIP_CAYMAN) {
+		dev_info(rdev->dev, "  R_00D834_DMA_STATUS_REG   = 0x%08X\n",
+			 RREG32(DMA_STATUS_REG + 0x800));
+	}
 }
 
-static bool evergreen_is_display_hung(struct radeon_device *rdev)
+bool evergreen_is_display_hung(struct radeon_device *rdev)
 {
 	u32 crtc_hung = 0;
 	u32 crtc_status[6];