Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932220AbcK1Gzs (ORCPT ); Mon, 28 Nov 2016 01:55:48 -0500 Received: from mail-io0-f172.google.com ([209.85.223.172]:36267 "EHLO mail-io0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752696AbcK1Gzl (ORCPT ); Mon, 28 Nov 2016 01:55:41 -0500 MIME-Version: 1.0 X-Originating-IP: [2a02:168:56b5:0:ac27:b86c:7764:9429] In-Reply-To: References: From: Daniel Vetter Date: Mon, 28 Nov 2016 07:55:39 +0100 Message-ID: Subject: Re: drm: GPF in drm_getcap To: David Herrmann , =?UTF-8?Q?Michel_D=C3=A4nzer?= Cc: Dmitry Vyukov , syzkaller , David Airlie , "dri-devel@lists.freedesktop.org" , LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id uAS6tqcF028394 Content-Length: 1442 Lines: 41 On Sat, Nov 26, 2016 at 7:22 PM, David Herrmann wrote: > On Sat, Nov 26, 2016 at 7:07 PM, Dmitry Vyukov wrote: >> grep "card0" dmesg: >> [ 5.298617] device: 'card0': device_add >> [ 5.298946] PM: Adding info for No Bus:card0 >> [ 6.436178] device: 'card0': device_add >> [ 6.436488] PM: Adding info for No Bus:card0 >> >> >> # ls -l /dev/dri/card0 >> crw-rw---T 1 root video 226, 0 Nov 26 18:05 /dev/dri/card0 >> >> # ls -lt /sys/class/drm/card0/device/ >> ls: cannot access /sys/class/drm/card0/device/: No such file or directory >> >> # ls -lt /sys/class/drm/card0/device/driver >> ls: cannot access /sys/class/drm/card0/device/driver: No such file or directory > > Looks like vgem. Something like this should help: > > https://gist.github.com/dvdhrm/1bcdf4f3485aa1614a0198a7b90515e2 > > I wonder whether it would be more appropriate to return -ENOTSUPP rather than 0. Seems a bit overkill, but can't hurt. This is most likely a regression, probably introduced in commit f837297ad82480024d3ad08cd84f6670bcafa862 Author: Michel Dänzer Date: Mon Aug 8 16:23:39 2016 +0900 drm: Add DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE/RELATIVE flags v2 Michel, can you pls take care of this? Either with a minimal fix, or by adopting David's patch? Thanks, Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch