drm/radeon: do a posting read in r600_set_irq

commit 9d1393f23d5656cdd5f368efd60694d4aeed81d3 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index 4cf21ec1abe39132dcab31b3a3c82beb7325c3b1..90b007594e32fb014a84efc2b1797a0c8a368209 100644 (file)
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -3459,6 +3459,9 @@ int r600_init(struct radeon_device *rdev)
                rdev->accel_working = false;
        }
 
+       /* posting read */
+       RREG32(R_000E50_SRBM_STATUS);
+
        return 0;
 }