drm/i915: Widen return value for reservation_object_wait_timeout_rcu to long.

This fixes a spurious warning from an integer overflow on 64-bits systems.
The function may return MAX_SCHEDULE_TIMEOUT which gets truncated to -1.

Explicitly handling this by casting to lret fixes it.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-and-tested-by: Joseph Yasi <joe.yasi@gmail.com>
Tested-by: Andreas Reis <andreas.reis@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: drm-intel-fixes@lists.freedesktop.org
Fixes: 3c28ff22f6e20c ("i915: wait for fence in prepare_plane_fb")
Link: http://patchwork.freedesktop.org/patch/msgid/5666EEC8.2000403@linux.intel.com
(cherry picked from commit bcf8be279c79df6a8a17d9c3e1f9bc926444a87c)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 11af6f5..e5b0e93 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13765,13 +13765,15 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 
        /* For framebuffer backed by dmabuf, wait for fence */
        if (obj && obj->base.dma_buf) {
-               ret = reservation_object_wait_timeout_rcu(obj->base.dma_buf->resv,
-                                                         false, true,
-                                                         MAX_SCHEDULE_TIMEOUT);
-               if (ret == -ERESTARTSYS)
-                       return ret;
+               long lret;
+
+               lret = reservation_object_wait_timeout_rcu(obj->base.dma_buf->resv,
+                                                          false, true,
+                                                          MAX_SCHEDULE_TIMEOUT);
+               if (lret == -ERESTARTSYS)
+                       return lret;
 
-               WARN_ON(ret < 0);
+               WARN(lret < 0, "waiting returns %li\n", lret);
        }
 
        if (!obj) {