Upstream commit 5cf0791da5c162ebc14b01eb01631cfa7ed4fa6e This patch is already part of various stable tree but is missing in the v3.18 v4.1 tree and applies cleanly on top of v3.18.69 v4.1.43 I've been contacted by Bernhard Kaindl (Cc:) and he asked about the whereabouts of the patch in the two stable trees. He can confirm that this patch cures his problem on the v3.18 stable tree he is using. He assumes that the same problem might occur on the v4.1 tree and should be fixed by the patch but he has no working setup with v4.1 kernel to confirm this. Sebastian