From patchwork Wed Jan 25 12:56:35 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 9537015 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id ED59F6046A for ; Wed, 25 Jan 2017 12:56:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DF5D227F17 for ; Wed, 25 Jan 2017 12:56:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D447E27FA6; Wed, 25 Jan 2017 12:56:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7373E27F17 for ; Wed, 25 Jan 2017 12:56:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A7609896B0; Wed, 25 Jan 2017 12:56:38 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id EA1A86E9C4 for ; Wed, 25 Jan 2017 12:56:37 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 3AB90ADA7; Wed, 25 Jan 2017 12:56:35 +0000 (UTC) Date: Wed, 25 Jan 2017 13:56:35 +0100 Message-ID: From: Takashi Iwai To: intel-gfx User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.1 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Cc: Michal Marek , "Chen, Angus" , Jeffrey Cheung , "Hsu, Ray" , Sridhara.Venkatanara@dell.com Subject: [Intel-gfx] Broken DPMS with DisplayPort on CHV (also BYT?) X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP Hi, we've got a bug report about the blank monitor on Cherry Trail machines. And, Intel team (Cc'ed) spotted out that this seems triggered by DPMS transition. A patch like below actually fixes the problem. Of course it doesn't look like a right "fix". Do you guys have any hint for further debugging? Some more (not alt-) facts: - The machine we've tested is a Cherry Trail based box with two DisplayPorts. Intel team mentioned that there are other machines suffering from the same problem. - With some monitors, the screen remains blank during boot and on X. This can be cured after "xset dpms force off" and resume, or reconfiguring via xrandr. - The issue seems specific to DP connections. When two (identical) monitors are connected, only one monitor goes blank. - The issue happens only with some monitor models (Dell E-series). Other Dell monitors (e.g. U-series) or other vendors seem working as far as we've tested. - Intel team mentioned that a similar issue was seen on a Baytrail machine. - The register value seems passed correctly. The read back after the register write showed the expected value. Also, spinning more times in DPMS_ON loop didn't help, too. - The issue is reproduced with the recent kernels (at least 4.9.x) Any comments / suggestions appreciated. thanks, Takashi --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -2205,8 +2205,12 @@ void intel_dp_sink_dpms(struct intel_dp return; if (mode != DRM_MODE_DPMS_ON) { +#if 0 ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER, DP_SET_POWER_D3); +#else + ret = 1; +#endif } else { /* * When turning on, we need to retry for 1ms to give the sink