From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4097AECE560 for ; Mon, 17 Sep 2018 18:16:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06C5F214EE for ; Mon, 17 Sep 2018 18:16:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 06C5F214EE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728533AbeIQXpX (ORCPT ); Mon, 17 Sep 2018 19:45:23 -0400 Received: from mga05.intel.com ([192.55.52.43]:32650 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727672AbeIQXpX (ORCPT ); Mon, 17 Sep 2018 19:45:23 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Sep 2018 11:16:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,386,1531810800"; d="scan'208";a="73961672" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by orsmga008.jf.intel.com with SMTP; 17 Sep 2018 11:16:41 -0700 Received: by stinkbox (sSMTP sendmail emulation); Mon, 17 Sep 2018 21:16:41 +0300 Date: Mon, 17 Sep 2018 21:16:41 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Lyude Paul Cc: dri-devel@lists.freedesktop.org, Sean Paul , David Airlie , linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/probe_helper: Don't bother probing when connectors are forced off Message-ID: <20180917181641.GQ5565@intel.com> References: <20180917174344.22011-1-lyude@redhat.com> <20180917175545.GP5565@intel.com> <54c01a13f382aacd7cd4d75a642630053f54b8f1.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <54c01a13f382aacd7cd4d75a642630053f54b8f1.camel@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 17, 2018 at 02:10:02PM -0400, Lyude Paul wrote: > On Mon, 2018-09-17 at 20:55 +0300, Ville Syrjälä wrote: > > On Mon, Sep 17, 2018 at 01:43:44PM -0400, Lyude Paul wrote: > > > Userspace asked them to be forced off, so why would we care about what a > > > probe tells us? > > > > I believe there should be force checks in the callers already. > > Or are we missing some? > > JFYI, what triggered me to send this patch are these error messages that come > from nouveau when a hotplug happens on a port that we've forced off: > > [ 1903.918104] nouveau 0000:01:00.0: DRM: DDC responded, but no EDID for DP-2 > [ 1903.918123] [drm:drm_helper_hpd_irq_event [drm_kms_helper]] [CONNECTOR:61:DP-2] status updated from disconnected to disconnected > > That being said; I'm sure there are probably some checks missing, but I don't > really see the purpose in calling the driver's probe functions at all if they're > just supposed to return the status we forced. Digging through my cobweb ridden local git repository I found this: commit bbd17813a7c7d0210c619365707044d0fb29e3f0 Author: Ville Syrjälä Date: Mon Jun 10 15:28:55 2013 +0300 drm: Ignore forced connectors in drm_helper_hpd_irq_event() drm_helper_hpd_irq_event() calls the connector's .detect() function even for forced connectors. If the returned status doesn't match the forced status, we will send the hotplug event, causing userspace to re-probe all the connectors. Eventually we should end up back where we started when drm_helper_probe_single_connector_modes() overwrites the connector status with the forced status. We can avoid all that pointles work if we just skip forced connectors in drm_helper_hpd_irq_event(). Signed-off-by: Ville Syrjälä diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c index ed1334e27c33..4fc2ad76c107 100644 --- a/drivers/gpu/drm/drm_crtc_helper.c +++ b/drivers/gpu/drm/drm_crtc_helper.c @@ -1086,6 +1086,10 @@ void drm_helper_hpd_irq_event(struct drm_device *dev) mutex_lock(&dev->mode_config.mutex); list_for_each_entry(connector, &dev->mode_config.connector_list, head) { + /* Ignore forced connectors. */ + if (connector->force) + continue; + /* Only handle HPD capable connectors. */ if (!(connector->polled & DRM_CONNECTOR_POLL_HPD)) continue; I guess I never sent it out. -- Ville Syrjälä Intel