drm/radeon/kms: unpin fb in atombios crtc disable

When drm_helper_disable_unused_functions calls disable
function of the CRTC, it also sets the crtc->fb pointer
to NULL. This can later (when the mode on that CRTC is setup
again from user space) cause ***_do_set_base functions to
"think" that there is no old buffer and skip the unpinning
code. Consequently, the buffer that has been NULL-ified in
drm_helper_disable_unused_functions will never be unpinned
causing a leak in VRAM.

This patch plugs the leak by unpinning the frame buffer
in crtc_disable function.

Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 86d9ee08b13f..4ad156267381 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -1910,6 +1910,21 @@ static void atombios_crtc_disable(struct drm_crtc *crtc)
         int i;
 
         atombios_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
+        if (crtc->fb) {
+                int r;
+                struct radeon_framebuffer *radeon_fb;
+                struct radeon_bo *rbo;
+
+                radeon_fb = to_radeon_framebuffer(crtc->fb);
+                rbo = gem_to_radeon_bo(radeon_fb->obj);
+                r = radeon_bo_reserve(rbo, false);
+                if (unlikely(r))
+                        DRM_ERROR("failed to reserve rbo before unpin\n");
+                else {
+                        radeon_bo_unpin(rbo);
+                        radeon_bo_unreserve(rbo);
+                }
+        }
         /* disable the GRPH */
         if (ASIC_IS_DCE4(rdev))
                 WREG32(EVERGREEN_GRPH_ENABLE + radeon_crtc->crtc_offset, 0);