From 63a445d34e5edc8e59d9888e9837c34b02d51b91 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Mon, 2 Mar 2015 20:43:53 -0500
Subject: [PATCH] drm/radeon: do a posting read in si_set_irq

commit 0586915ec10d0ae60de5cd3381ad25a704760402 upstream.

To make sure the writes go through the pci bridge.

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=90741

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
 drivers/gpu/drm/radeon/si.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index e710073923e97..068b21f0d7df8 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -4126,6 +4126,9 @@ int si_init(struct radeon_device *rdev)
 		return -EINVAL;
 	}
 
+	/* posting read */
+	RREG32(SRBM_STATUS);
+
 	return 0;
 }
 
-- 
2.47.2