On Fri, 2018-09-21 at 11:27 +0200, Daniel Vetter wrote: > On Tue, Sep 18, 2018 at 07:06:19PM -0400, Lyude Paul wrote: > > Currently we set intel_connector->mst_port to NULL to signify that the > > MST port has been removed from the system so that we can prevent further > > action on the port such as connector probes, mode probing, etc. > > However, we're going to need access to intel_connector->mst_port in > > order to fixup ->best_encoder() so that it can always return the correct > > encoder for an MST port to prevent legacy DPMS prop changes from > > failing. This should be safe, so instead keep intel_connector->mst_port > > always set and instead add intel_connector->mst_port_gone in order to > > signify whether or not the connector has disappeared from the system. > > > > Signed-off-by: Lyude Paul <ly...@redhat.com> > > Cc: sta...@vger.kernel.org > > Hm, how exactly do legacy DPMS setprop blow up here? Or at least I can't > come up with a scenario that's specific to legacy props, atomic should be > equally affected. By the time we land in this code, the core code already > remapping it to be purely an atomic update. So, what I've been seeing with X that's been blowing this up: * Hotplug event gets received, X does reprobe * Notices MST connectors are now disconnected, sets DPMS from on->off * During atomic_check, drm_atomic_helper_check_modeset() is called * update_connector_routing() gets called * funcs->best_encoder() returns NULL for the encoder * update_connector_routing() fails atomic commit with "No suitable encoder found", line 320 of drm_atomic_helper > > Another thought: Should we handle at least some of this in the probe > helpers? I.e. once you unplugged a drm_connector, it always shows > disconnected and mode list is gone, instead of duplicating this over all > drivers. We could just check connector->registered. oooh, good idea! I will certainly go do that > > Thanks, Daniel > > --- > > drivers/gpu/drm/i915/intel_dp_mst.c | 14 +++++++------- > > drivers/gpu/drm/i915/intel_drv.h | 1 + > > 2 files changed, 8 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c > > b/drivers/gpu/drm/i915/intel_dp_mst.c > > index 4ecd65375603..fcb9b87b9339 100644 > > --- a/drivers/gpu/drm/i915/intel_dp_mst.c > > +++ b/drivers/gpu/drm/i915/intel_dp_mst.c > > @@ -311,9 +311,8 @@ static int intel_dp_mst_get_ddc_modes(struct > > drm_connector *connector) > > struct edid *edid; > > int ret; > > > > - if (!intel_dp) { > > + if (intel_connector->mst_port_gone) > > return intel_connector_update_modes(connector, NULL); > > - } > > > > edid = drm_dp_mst_get_edid(connector, &intel_dp->mst_mgr, > > intel_connector->port); > > ret = intel_connector_update_modes(connector, edid); > > @@ -328,9 +327,10 @@ intel_dp_mst_detect(struct drm_connector *connector, > > bool force) > > struct intel_connector *intel_connector = > > to_intel_connector(connector); > > struct intel_dp *intel_dp = intel_connector->mst_port; > > > > - if (!intel_dp) > > + if (intel_connector->mst_port_gone) > > return connector_status_disconnected; > > - return drm_dp_mst_detect_port(connector, &intel_dp->mst_mgr, > > intel_connector->port); > > + return drm_dp_mst_detect_port(connector, &intel_dp->mst_mgr, > > + intel_connector->port); > > } > > > > static void > > @@ -370,7 +370,7 @@ intel_dp_mst_mode_valid(struct drm_connector > > *connector, > > int bpp = 24; /* MST uses fixed bpp */ > > int max_rate, mode_rate, max_lanes, max_link_clock; > > > > - if (!intel_dp) > > + if (intel_connector->mst_port_gone) > > return MODE_ERROR; > > > > if (mode->flags & DRM_MODE_FLAG_DBLSCAN) > > @@ -402,7 +402,7 @@ static struct drm_encoder > > *intel_mst_atomic_best_encoder(struct drm_connector *c > > struct intel_dp *intel_dp = intel_connector->mst_port; > > struct intel_crtc *crtc = to_intel_crtc(state->crtc); > > > > - if (!intel_dp) > > + if (intel_connector->mst_port_gone) > > return NULL; > > return &intel_dp->mst_encoders[crtc->pipe]->base.base; > > } > > @@ -514,7 +514,7 @@ static void intel_dp_destroy_mst_connector(struct > > drm_dp_mst_topology_mgr *mgr, > > connector); > > /* prevent race with the check in ->detect */ > > drm_modeset_lock(&connector->dev->mode_config.connection_mutex, NULL); > > - intel_connector->mst_port = NULL; > > + intel_connector->mst_port_gone = true; > > drm_modeset_unlock(&connector->dev->mode_config.connection_mutex); > > > > drm_connector_put(connector); > > diff --git a/drivers/gpu/drm/i915/intel_drv.h > > b/drivers/gpu/drm/i915/intel_drv.h > > index 8fc61e96754f..87ce772ae7f8 100644 > > --- a/drivers/gpu/drm/i915/intel_drv.h > > +++ b/drivers/gpu/drm/i915/intel_drv.h > > @@ -409,6 +409,7 @@ struct intel_connector { > > void *port; /* store this opaque as its illegal to dereference it */ > > > > struct intel_dp *mst_port; > > + bool mst_port_gone; > > > > /* Work struct to schedule a uevent on link train failure */ > > struct work_struct modeset_retry_work; > > -- > > 2.17.1 > > > > _______________________________________________ > > Intel-gfx mailing list > > intel-...@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- Cheers, Lyude Paul
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