From: Sean Paul <sean@poorly.run>
To: Lyude Paul <lyude@redhat.com>
Cc: dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
amd-gfx@lists.freedesktop.org, "Juston Li" <juston.li@intel.com>,
"Imre Deak" <imre.deak@intel.com>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
"Harry Wentland" <hwentlan@amd.com>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Maxime Ripard" <mripard@kernel.org>,
"Sean Paul" <sean@poorly.run>, "David Airlie" <airlied@linux.ie>,
"Daniel Vetter" <daniel@ffwll.ch>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 21/27] drm/dp_mst: Don't forget to update port->input in drm_dp_mst_handle_conn_stat()
Date: Wed, 25 Sep 2019 16:03:27 -0400 [thread overview]
Message-ID: <20190925200327.GM218215@art_vandelay> (raw)
In-Reply-To: <20190903204645.25487-22-lyude@redhat.com>
On Tue, Sep 03, 2019 at 04:45:59PM -0400, Lyude Paul wrote:
> This probably hasn't caused any problems up until now since it's
> probably nearly impossible to encounter this in the wild, however if we
> were to receive a connection status notification from the MST hub after
> resume while we're in the middle of reprobing the link addresses for a
> topology then there's a much larger chance that a port could have
> changed from being an output port to input port (or vice versa). If we
> forget to update this bit of information, we'll potentially ignore a
> valid PDT change on a downstream port because we think it's an input
> port.
>
> So, make sure we read the input_port field in connection status
> notifications in drm_dp_mst_handle_conn_stat() to prevent this from
> happening once we've implemented suspend/resume reprobing.
>
> Cc: Juston Li <juston.li@intel.com>
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Harry Wentland <hwentlan@amd.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Signed-off-by: Lyude Paul <lyude@redhat.com>
Nice catch! Same comment here re: port->mutex, but we can sort that out on the
other thread
Reviewed-by: Sean Paul <sean@poorly.run>
> ---
> drivers/gpu/drm/drm_dp_mst_topology.c | 51 +++++++++++++++++++--------
> 1 file changed, 37 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 259634c5d6dc..e407aba1fbd2 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -2078,18 +2078,23 @@ static void
> drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
> struct drm_dp_connection_status_notify *conn_stat)
> {
> - struct drm_device *dev = mstb->mgr->dev;
> + struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
> + struct drm_device *dev = mgr->dev;
> struct drm_dp_mst_port *port;
> - int old_ddps;
> - bool dowork = false;
> + struct drm_connector *connector_to_destroy = NULL;
> + int old_ddps, ret;
> + u8 new_pdt;
> + bool dowork = false, create_connector = false;
>
> port = drm_dp_get_port(mstb, conn_stat->port_number);
> if (!port)
> return;
>
> + mutex_lock(&port->lock);
> drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
>
> old_ddps = port->ddps;
> + port->input = conn_stat->input_port;
> port->mcs = conn_stat->message_capability_status;
> port->ldps = conn_stat->legacy_device_plug_status;
> port->ddps = conn_stat->displayport_device_plug_status;
> @@ -2102,23 +2107,41 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
> }
> }
>
> - if (!port->input) {
> - int ret = drm_dp_port_set_pdt(port,
> - conn_stat->peer_device_type);
> - if (ret == 1) {
> - dowork = true;
> - } else if (ret < 0) {
> - DRM_ERROR("Failed to change PDT for port %p: %d\n",
> - port, ret);
> - dowork = false;
> - }
> + new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
> +
> + ret = drm_dp_port_set_pdt(port, new_pdt);
> + if (ret == 1) {
> + dowork = true;
> + } else if (ret < 0) {
> + DRM_ERROR("Failed to change PDT for port %p: %d\n",
> + port, ret);
> + dowork = false;
> + }
> +
> + /*
> + * We unset port->connector before dropping connection_mutex so that
> + * there's no chance any of the atomic MST helpers can accidentally
> + * associate a to-be-destroyed connector with a port.
> + */
> + if (port->connector && port->input) {
> + connector_to_destroy = port->connector;
> + port->connector = NULL;
> + } else if (!port->connector && !port->input) {
> + create_connector = true;
> }
>
> drm_modeset_unlock(&dev->mode_config.connection_mutex);
> +
> + if (connector_to_destroy)
> + mgr->cbs->destroy_connector(mgr, connector_to_destroy);
> + else if (create_connector)
> + drm_dp_mst_port_add_connector(mstb, port);
> +
> + mutex_unlock(&port->lock);
> +
> drm_dp_mst_topology_put_port(port);
> if (dowork)
> queue_work(system_long_wq, &mstb->mgr->work);
> -
> }
>
> static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
> --
> 2.21.0
>
--
Sean Paul, Software Engineer, Google / Chromium OS
next prev parent reply other threads:[~2019-09-25 20:03 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190903204645.25487-1-lyude@redhat.com>
2019-09-03 20:45 ` [PATCH v2 01/27] drm/dp_mst: Move link address dumping into a function Lyude Paul
2019-09-25 17:45 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 02/27] drm/dp_mst: Get rid of list clear in destroy_connector_work Lyude Paul
2019-09-25 17:45 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 03/27] drm/dp_mst: Destroy MSTBs asynchronously Lyude Paul
2019-09-25 18:16 ` Sean Paul
2019-09-25 20:08 ` Lyude Paul
2019-09-27 13:31 ` Sean Paul
2019-10-08 9:45 ` Daniel Vetter
2019-09-03 20:45 ` [PATCH v2 04/27] drm/dp_mst: Move test_calc_pbn_mode() into an actual selftest Lyude Paul
2019-09-25 18:17 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 05/27] drm/print: Add drm_err_printer() Lyude Paul
2019-09-03 20:45 ` [PATCH v2 06/27] drm/dp_mst: Combine redundant cases in drm_dp_encode_sideband_req() Lyude Paul
2019-09-03 21:35 ` Dave Airlie
2019-09-03 21:57 ` [PATCH v3] " Lyude Paul
2019-09-03 20:45 ` [PATCH v2 07/27] drm/dp_mst: Add sideband down request tracing + selftests Lyude Paul
2019-09-10 9:01 ` Jani Nikula
2019-09-03 20:45 ` [PATCH v2 08/27] drm/dp_mst: Remove PDT teardown in drm_dp_destroy_port() and refactor Lyude Paul
2019-09-25 19:00 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 09/27] drm/dp_mst: Refactor drm_dp_send_enum_path_resources Lyude Paul
2019-09-03 20:45 ` [PATCH v2 10/27] drm/dp_mst: Remove huge conditional in drm_dp_mst_handle_up_req() Lyude Paul
2019-09-03 20:45 ` [PATCH v2 11/27] drm/dp_mst: Constify guid in drm_dp_get_mst_branch_by_guid() Lyude Paul
2019-09-03 21:41 ` Dave Airlie
2019-09-03 20:45 ` [PATCH v2 12/27] drm/dp_mst: Refactor drm_dp_mst_handle_up_req() Lyude Paul
2019-09-03 20:45 ` [PATCH v2 13/27] drm/dp_mst: Refactor drm_dp_mst_handle_down_rep() Lyude Paul
2019-09-03 20:45 ` [PATCH v2 14/27] drm/dp_mst: Destroy topology_mgr mutexes Lyude Paul
2019-09-25 19:14 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 15/27] drm/dp_mst: Cleanup drm_dp_send_link_address() a bit Lyude Paul
2019-09-03 21:42 ` Dave Airlie
2019-09-03 20:45 ` [PATCH v2 16/27] drm/dp_mst: Refactor pdt setup/teardown, add more locking Lyude Paul
2019-09-25 19:27 ` Sean Paul
2019-09-25 21:00 ` Lyude Paul
2019-09-27 13:30 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 17/27] drm/dp_mst: Rename drm_dp_add_port and drm_dp_update_port Lyude Paul
2019-09-25 19:30 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 18/27] drm/dp_mst: Remove lies in {up,down}_rep_recv documentation Lyude Paul
2019-09-25 19:32 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 19/27] drm/dp_mst: Handle UP requests asynchronously Lyude Paul
2019-09-25 19:46 ` Sean Paul
2019-09-03 20:45 ` [PATCH v2 20/27] drm/dp_mst: Protect drm_dp_mst_port members with connection_mutex Lyude Paul
2019-09-25 20:00 ` Sean Paul
2019-09-25 21:01 ` Lyude Paul
2019-09-03 20:45 ` [PATCH v2 21/27] drm/dp_mst: Don't forget to update port->input in drm_dp_mst_handle_conn_stat() Lyude Paul
2019-09-25 20:03 ` Sean Paul [this message]
2019-09-03 20:46 ` [PATCH v2 22/27] drm/nouveau: Don't grab runtime PM refs for HPD IRQs Lyude Paul
2019-09-25 20:06 ` Sean Paul
2019-09-03 20:46 ` [PATCH v2 23/27] drm/amdgpu: Iterate through DRM connectors correctly Lyude Paul
2019-09-13 20:45 ` Alex Deucher
2019-09-27 13:48 ` Alex Deucher
2019-09-03 20:46 ` [PATCH v2 24/27] drm/amdgpu/dm: Resume short HPD IRQs before resuming MST topology Lyude Paul
2019-09-13 20:46 ` Alex Deucher
2019-09-25 20:08 ` Sean Paul
2019-09-25 21:52 ` [PATCH v4] " Lyude Paul
2019-09-27 13:29 ` Alex Deucher
2019-09-03 20:46 ` [PATCH v2 25/27] drm/dp_mst: Add basic topology reprobing when resuming Lyude Paul
2019-09-27 13:52 ` Sean Paul
2019-10-09 19:06 ` Lyude Paul
2019-09-03 20:46 ` [PATCH v2 26/27] drm/dp_mst: Also print unhashed pointers for malloc/topology references Lyude Paul
2019-09-27 14:25 ` Sean Paul
2019-10-09 19:40 ` Lyude Paul
2019-09-03 20:46 ` [PATCH v2 27/27] drm/dp_mst: Add topology ref history tracking for debugging Lyude Paul
2019-09-27 14:51 ` Sean Paul
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