From: Alex Deucher <alexander.deucher@amd.com>
Date: Tue, 3 Mar 2015 01:36:26 +0000 (-0500)
Subject: drm/radeon: do a posting read in r100_set_irq
X-Git-Tag: v3.4.108~110
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e653b3ede2c327db4310f8053286521e471c9c0a;p=thirdparty%2Fkernel%2Fstable.git

drm/radeon: do a posting read in r100_set_irq

commit f957063fee6392bb9365370db6db74dc0b2dce0a 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>
---

diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index 40ed0e5b95a3b..8ec5b85538735 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -726,6 +726,10 @@ int r100_irq_set(struct radeon_device *rdev)
 		tmp |= RADEON_FP2_DETECT_MASK;
 	}
 	WREG32(RADEON_GEN_INT_CNTL, tmp);
+
+	/* read back to post the write */
+	RREG32(RADEON_GEN_INT_CNTL);
+
 	return 0;
 }