drm/i915: Handle error return from dma_set_coherent_mask()

A failure from these functions can lead to obscure bugs later, so it's
better not to suppress them and just fail module loading.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463059132-1720-4-git-send-email-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 05b2b1901d60d3d9f5162bc1b35dfe799416ddac..547100fa31222f1aecabce67aa0df80235f76984 100644 (file)
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1262,8 +1262,15 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
        pci_set_master(dev->pdev);
 
        /* overlay on gen2 is broken and can't address above 1G */
-       if (IS_GEN2(dev))
-               dma_set_coherent_mask(&dev->pdev->dev, DMA_BIT_MASK(30));
+       if (IS_GEN2(dev)) {
+               ret = dma_set_coherent_mask(&dev->pdev->dev, DMA_BIT_MASK(30));
+               if (ret) {
+                       DRM_ERROR("failed to set DMA mask\n");
+
+                       goto out_ggtt;
+               }
+       }
+
 
        /* 965GM sometimes incorrectly writes to hardware status page (HWS)
         * using 32bit addressing, overwriting memory if HWS is located
@@ -1273,8 +1280,15 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
         * behaviour if any general state is accessed within a page above 4GB,
         * which also needs to be handled carefully.
         */
-       if (IS_BROADWATER(dev) || IS_CRESTLINE(dev))
-               dma_set_coherent_mask(&dev->pdev->dev, DMA_BIT_MASK(32));
+       if (IS_BROADWATER(dev) || IS_CRESTLINE(dev)) {
+               ret = dma_set_coherent_mask(&dev->pdev->dev, DMA_BIT_MASK(32));
+
+               if (ret) {
+                       DRM_ERROR("failed to set DMA mask\n");
+
+                       goto out_ggtt;
+               }
+       }
 
        aperture_size = ggtt->mappable_end;