[PATCH 3.4 065/172] drm/radeon: do a posting read in rs600_set_irq

[lizf]

From: Alex Deucher <alexander.deucher@xxxxxxx>

3.4.108-rc1 review patch.  If anyone has any objections, please let me know.

------------------


commit 54acf107e4e66d1f4a697e08a7f60dba9fcf07c3 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@xxxxxxx>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
---
 drivers/gpu/drm/radeon/rs600.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/radeon/rs600.c b/drivers/gpu/drm/radeon/rs600.c
index 739eb0d..07b6dbf 100644
--- a/drivers/gpu/drm/radeon/rs600.c
+++ b/drivers/gpu/drm/radeon/rs600.c
@@ -585,6 +585,10 @@ int rs600_irq_set(struct radeon_device *rdev)
 	WREG32(R_006540_DxMODE_INT_MASK, mode_int);
 	WREG32(R_007D08_DC_HOT_PLUG_DETECT1_INT_CONTROL, hpd1);
 	WREG32(R_007D18_DC_HOT_PLUG_DETECT2_INT_CONTROL, hpd2);
+
+	/* posting read */
+	RREG32(R_000040_GEN_INT_CNTL);
+
 	return 0;
 }
 
-- 
1.9.1

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