From mboxrd@z Thu Jan 1 00:00:00 1970 From: Darren Hart Subject: Re: [PATCH] drm/i915/vlv: reset VLV media force wake request register Date: Fri, 09 May 2014 11:09:58 -0700 Message-ID: References: <1399639278-30941-1-git-send-email-jani.nikula@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTP id 55D3F6E023 for ; Fri, 9 May 2014 11:10:13 -0700 (PDT) In-Reply-To: <1399639278-30941-1-git-send-email-jani.nikula@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Jani Nikula , intel-gfx@lists.freedesktop.org, Imre Deak List-Id: intel-gfx@lists.freedesktop.org On 5/9/14, 5:41, "Jani Nikula" wrote: >Media force wake get hangs the machine when the system is booted without >displays attached. The assumption is that (at least some versions of) >the firmware has skipped some initialization in that case. > >Empirical evidence suggests we need to reset the media force wake >request register in addition to the render one to avoid hangs. > >Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75895 >Reported-by: Imre Deak >Reported-by: Darren Hart >Cc: stable@vger.kernel.org >Signed-off-by: Jani Nikula Applied to 3.14.2 and tested on MinnowBoardMax A0 hardware (BayTrail-I, Atom E3825). * With no display connected, the boot no longer hangs and DRM prints sensible messages during boot: [ 5.968837] [drm] GMBUS [i915 gmbus vga] timed out, falling back to bit banging on pin 2 [ 5.988037] i915 0000:00:02.0: No connectors reported connected with modes [ 5.995744] [drm] Cannot find any crtc or sizes - going 1024x768 [ 6.004716] fbcon: inteldrmfb (fb0) is primary device [ 6.013066] Console: switching to colour frame buffer device 128x48 [ 6.034147] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device [ 6.041168] i915 0000:00:02.0: registered panic notifier [ 6.049820] ACPI: Video Device [GFX0] (multi-head: yes rom: no post: no) [ 6.058788] acpi device:30: registered as cooling_device3 [ 6.065111] input: Video Bus as /devices/LNXSYSTM:00/device:00/PNP0A08:00/LNXVIDEO:00/input/input4 [ 6.075370] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0 * If a display is subsequently connected and X is restarted, it behaves as expected. * Booting with a display connected continue to work as expected. Tested-by: Darren Hart Thank you very much Jani! -- Darren Hart Open Source Technology Center darren.hart@intel.com Intel Corporation