From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755277AbcEZWLq (ORCPT ); Thu, 26 May 2016 18:11:46 -0400 Received: from mail-oi0-f66.google.com ([209.85.218.66]:35510 "EHLO mail-oi0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754733AbcEZWLp (ORCPT ); Thu, 26 May 2016 18:11:45 -0400 From: Larry Finger Subject: Regression in i915 in kernel 4.6.0-git - bisected to f21a21983ef13a031 To: Shubhangi Shrivastava , Jani Nikula , Daniel Vetter Cc: intel-gfx@lists.freedesktop.org, DRI , LKML Message-ID: <5747749E.8040609@lwfinger.net> Date: Thu, 26 May 2016 17:11:42 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The latest mainline kernel (commit 3f59de0) shows a regression. The symptom is that as soon as the kernel is started, the display is blanked, and it is never turned on again. This problem was bisected to commit f21a21983ef13a031250c4c3f6018e29a549d0f1 ("drm/i915: Splitting intel_dp_detect"). The adapter in question is the integrated graphics controller on a Toshiba Tecra A50 laptop. The output of "lspci -nnv" for that controller is as follows: 00:02.0 VGA compatible controller [0300]: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller [8086:0416] (rev 06) (prog-if 00 [VGA controller]) Subsystem: Toshiba America Info Systems Device [1179:0002] Flags: bus master, fast devsel, latency 0, IRQ 27 Memory at e0000000 (64-bit, non-prefetchable) [size=4M] Memory at d0000000 (64-bit, prefetchable) [size=256M] I/O ports at 4000 [size=64] Expansion ROM at [disabled] Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit- Capabilities: [d0] Power Management version 2 Capabilities: [a4] PCI Advanced Features Kernel driver in use: i915 Kernel modules: i915 If the kernel is booted with "nomodeset", the display is normal. I will be happy to test any patches, or to answer any further questions. Thanks, Larry