drm/radeon: do a posting read in evergreen_set_irq

commit c320bb5f6dc0cb88a811cbaf839303e0a3916a92 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/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index 7138f3e31b7c01ad40ba22b6d1ace9270a606d73..ee9f0b4e90d6c7290379eab004f776d86a0ec66f 100644 (file)
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -4596,6 +4596,9 @@ int evergreen_irq_set(struct radeon_device *rdev)
        WREG32(AFMT_AUDIO_PACKET_CONTROL + EVERGREEN_CRTC4_REGISTER_OFFSET, afmt5);
        WREG32(AFMT_AUDIO_PACKET_CONTROL + EVERGREEN_CRTC5_REGISTER_OFFSET, afmt6);
 
+       /* posting read */
+       RREG32(SRBM_STATUS);
+
        return 0;
 }