From 79a47cd36c8ddbf4435cd658d00c61cc2d9741cd Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Thu, 10 Jan 2019 19:53:33 -0500 Subject: drm/i915: Keep malloc references to MST ports So that the ports stay around until we've destroyed the connectors, in order to ensure that we don't pass an invalid pointer to any MST helpers once we introduce the new MST VCPI helpers. Changes since v1: * Move drm_dp_mst_get_port_malloc() to where we assign intel_connector->port - danvet Signed-off-by: Lyude Paul Reviewed-by: Daniel Vetter Cc: David Airlie Cc: Jerry Zuo Cc: Harry Wentland Cc: Juston Li Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-11-lyude@redhat.com --- drivers/gpu/drm/i915/intel_dp_mst.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/gpu/drm/i915/intel_dp_mst.c') diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index f05427b74e34..631fd1537252 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -457,6 +457,7 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo intel_connector->get_hw_state = intel_dp_mst_get_hw_state; intel_connector->mst_port = intel_dp; intel_connector->port = port; + drm_dp_mst_get_port_malloc(port); connector = &intel_connector->base; ret = drm_connector_init(dev, connector, &intel_dp_mst_connector_funcs, -- cgit v1.2.2 From eceae147246749c6dbaeefda802b30f804a3c54c Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Thu, 10 Jan 2019 19:53:41 -0500 Subject: drm/dp_mst: Start tracking per-port VCPI allocations There has been a TODO waiting for quite a long time in drm_dp_mst_topology.c: /* We cannot rely on port->vcpi.num_slots to update * topology_state->avail_slots as the port may not exist if the parent * branch device was unplugged. This should be fixed by tracking * per-port slot allocation in drm_dp_mst_topology_state instead of * depending on the caller to tell us how many slots to release. */ That's not the only reason we should fix this: forcing the driver to track the VCPI allocations throughout a state's atomic check is error prone, because it means that extra care has to be taken with the order that drm_dp_atomic_find_vcpi_slots() and drm_dp_atomic_release_vcpi_slots() are called in in order to ensure idempotency. Currently the only driver actually using these helpers, i915, doesn't even do this correctly: multiple ->best_encoder() checks with i915's current implementation would not be idempotent and would over-allocate VCPI slots, something I learned trying to implement fallback retraining in MST. So: simplify this whole mess, and teach drm_dp_atomic_find_vcpi_slots() and drm_dp_atomic_release_vcpi_slots() to track the VCPI allocations for each port. This allows us to ensure idempotency without having to rely on the driver as much. Additionally: the driver doesn't need to do any kind of VCPI slot tracking anymore if it doesn't need it for it's own internal state. Additionally; this adds a new drm_dp_mst_atomic_check() helper which must be used by atomic drivers to perform validity checks for the new VCPI allocations incurred by a state. Also: update the documentation and make it more obvious that these /must/ be called by /all/ atomic drivers supporting MST. Changes since v9: * Add some missing changes that were requested by danvet that I forgot about after I redid all of the kref stuff: * Remove unnecessary state changes in intel_dp_mst_atomic_check * Cleanup atomic check logic for VCPI allocations - all we need to check in compute_config is whether or not this state disables a CRTC, then free VCPI based off that Changes since v8: * Fix compile errors, whoops! Changes since v7: - Don't check for mixed stale/valid VCPI allocations, just rely on connector registration to stop such erroneous modesets Changes since v6: - Keep a kref to all of the ports we have allocations on. This required a good bit of changing to when we call drm_dp_find_vcpi_slots(), mainly that we need to ensure that we only redo VCPI allocations on actual mode or CRTC changes, not crtc_state->active changes. Additionally, we no longer take the registration of the DRM connector for each port into account because so long as we have a kref to the port in the new or previous atomic state, the connector will stay registered. - Use the small changes to drm_dp_put_port() to add even more error checking to make misusage of the helpers more obvious. I added this after having to chase down various use-after-free conditions that started popping up from the new helpers so no one else has to troubleshoot that. - Move some accidental DRM_DEBUG_KMS() calls to DRM_DEBUG_ATOMIC() - Update documentation again, note that find/release() should both not be called on the same port in a single atomic check phase (but multiple calls to one or the other is OK) Changes since v4: - Don't skip the atomic checks for VCPI allocations if no new VCPI allocations happen in a state. This makes the next change I'm about to list here a lot easier to implement. - Don't ignore VCPI allocations on destroyed ports, instead ensure that when ports are destroyed and still have VCPI allocations in the topology state, the only state changes allowed are releasing said ports' VCPI. This prevents a state with a mix of VCPI allocations from destroyed ports, and allocations from valid ports. Changes since v3: - Don't release VCPI allocations in the topology state immediately in drm_dp_atomic_release_vcpi_slots(), instead mark them as 0 and skip over them in drm_dp_mst_duplicate_state(). This makes it so drm_dp_atomic_release_vcpi_slots() is still idempotent while also throwing warnings if the driver messes up it's book keeping and tries to release VCPI slots on a port that doesn't have any pre-existing VCPI allocation - danvet - Change mst_state/state in some debugging messages to "mst state" Changes since v2: - Use kmemdup() for duplicating MST state - danvet - Move port validation out of duplicate state callback - danvet - Handle looping through MST topology states in drm_dp_mst_atomic_check() so the driver doesn't have to do it - Fix documentation in drm_dp_atomic_find_vcpi_slots() - Move the atomic check for each individual topology state into it's own function, reduces indenting - Don't consider "stale" MST ports when calculating the bandwidth requirements. This is needed because originally we relied on the state duplication functions to prune any stale ports from the new state, which would prevent us from incorrectly considering their bandwidth requirements alongside legitimate new payloads. - Add function references in drm_dp_atomic_release_vcpi_slots() - danvet - Annotate atomic VCPI and atomic check functions with __must_check - danvet Changes since v1: - Don't use the now-removed ->atomic_check() for private objects hook, just give drivers a function to call themselves Signed-off-by: Lyude Paul Reviewed-by: Daniel Vetter Cc: David Airlie Cc: Jerry Zuo Cc: Harry Wentland Cc: Juston Li Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-19-lyude@redhat.com --- drivers/gpu/drm/i915/intel_dp_mst.c | 54 +++++++++++++++++++++---------------- 1 file changed, 31 insertions(+), 23 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_dp_mst.c') diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index 631fd1537252..c8e2215628e6 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -41,8 +41,12 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, struct drm_connector *connector = conn_state->connector; void *port = to_intel_connector(connector)->port; struct drm_atomic_state *state = pipe_config->base.state; + struct drm_crtc *crtc = pipe_config->base.crtc; + struct drm_crtc_state *old_crtc_state = + drm_atomic_get_old_crtc_state(state, crtc); int bpp; - int lane_count, slots = 0; + int lane_count, slots = + to_intel_crtc_state(old_crtc_state)->dp_m_n.tu; const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode; int mst_pbn; bool constant_n = drm_dp_has_quirk(&intel_dp->desc, @@ -107,35 +111,39 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, return true; } -static int intel_dp_mst_atomic_check(struct drm_connector *connector, - struct drm_connector_state *new_conn_state) +static int +intel_dp_mst_atomic_check(struct drm_connector *connector, + struct drm_connector_state *new_conn_state) { struct drm_atomic_state *state = new_conn_state->state; - struct drm_connector_state *old_conn_state; - struct drm_crtc *old_crtc; + struct drm_connector_state *old_conn_state = + drm_atomic_get_old_connector_state(state, connector); + struct intel_connector *intel_connector = + to_intel_connector(connector); + struct drm_crtc *new_crtc = new_conn_state->crtc; struct drm_crtc_state *crtc_state; - int slots, ret = 0; + struct drm_dp_mst_topology_mgr *mgr; + int ret = 0; - old_conn_state = drm_atomic_get_old_connector_state(state, connector); - old_crtc = old_conn_state->crtc; - if (!old_crtc) - return ret; - - crtc_state = drm_atomic_get_new_crtc_state(state, old_crtc); - slots = to_intel_crtc_state(crtc_state)->dp_m_n.tu; - if (drm_atomic_crtc_needs_modeset(crtc_state) && slots > 0) { - struct drm_dp_mst_topology_mgr *mgr; - struct drm_encoder *old_encoder; + if (!old_conn_state->crtc) + return 0; - old_encoder = old_conn_state->best_encoder; - mgr = &enc_to_mst(old_encoder)->primary->dp.mst_mgr; + /* We only want to free VCPI if this state disables the CRTC on this + * connector + */ + if (new_crtc) { + crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc); - ret = drm_dp_atomic_release_vcpi_slots(state, mgr, slots); - if (ret) - DRM_DEBUG_KMS("failed releasing %d vcpi slots:%d\n", slots, ret); - else - to_intel_crtc_state(crtc_state)->dp_m_n.tu = 0; + if (!crtc_state || + !drm_atomic_crtc_needs_modeset(crtc_state) || + crtc_state->enable) + return 0; } + + mgr = &enc_to_mst(old_conn_state->best_encoder)->primary->dp.mst_mgr; + ret = drm_dp_atomic_release_vcpi_slots(state, mgr, + intel_connector->port); + return ret; } -- cgit v1.2.2 From 96550555a78ca3c9fda4b358549a5622810fe32c Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Tue, 15 Jan 2019 15:08:00 -0500 Subject: drm/i915: Pass down rc in intel_encoder->compute_config() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Something that I completely missed when implementing the new MST VCPI atomic helpers is that with those helpers, there's technically a chance of us having to grab additional modeset locks in ->compute_config() and furthermore, that means we have the potential to hit a normal modeset deadlock. However, because ->compute_config() only returns a bool this means we can't return -EDEADLK when we need to drop locks and try again which means we end up just failing the atomic check permanently. Whoops. So, fix this by modifying ->compute_config() to pass down an actual error code instead of a bool so that the atomic check can be restarted on modeset deadlocks. Thanks to Ville Syrjälä for pointing this out! Changes since v1: * Add some newlines * Return only -EINVAL from hsw_crt_compute_config() * Propogate return code from intel_dp_compute_dsc_params() * Change all of the intel_dp_compute_link_config*() variants * Don't miss if (hdmi_port_clock_valid()) branch in intel_hdmi_compute_config() Signed-off-by: Lyude Paul Cc: Ville Syrjälä Fixes: eceae1472467 ("drm/dp_mst: Start tracking per-port VCPI allocations") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109320 Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20190115200800.3121-1-lyude@redhat.com --- drivers/gpu/drm/i915/intel_dp_mst.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_dp_mst.c') diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index c8e2215628e6..5899debe2184 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -30,9 +30,9 @@ #include #include -static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, - struct intel_crtc_state *pipe_config, - struct drm_connector_state *conn_state) +static int intel_dp_mst_compute_config(struct intel_encoder *encoder, + struct intel_crtc_state *pipe_config, + struct drm_connector_state *conn_state) { struct drm_i915_private *dev_priv = to_i915(encoder->base.dev); struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base); @@ -53,7 +53,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, DP_DPCD_QUIRK_CONSTANT_N); if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN) - return false; + return -EINVAL; pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB; pipe_config->has_pch_encoder = false; @@ -90,7 +90,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, if (slots < 0) { DRM_DEBUG_KMS("failed finding vcpi slots:%d\n", slots); - return false; + return slots; } } @@ -108,7 +108,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, intel_ddi_compute_min_voltage_level(dev_priv, pipe_config); - return true; + return 0; } static int -- cgit v1.2.2