From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [PATCH] drm/probe_helper: Don't bother probing when connectors are forced off Date: Mon, 17 Sep 2018 21:16:41 +0300 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-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <54c01a13f382aacd7cd4d75a642630053f54b8f1.camel@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Lyude Paul Cc: dri-devel@lists.freedesktop.org, Sean Paul , David Airlie , linux-kernel@vger.kernel.org List-Id: dri-devel@lists.freedesktop.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