Re: [Intel-gfx] [PATCH 1/6] drm/dp_mst: Introduce drm_dp_mst_connector_atomic_check()
On 2018-09-18 07:06 PM, Lyude Paul wrote: > Currently the way that we prevent userspace from performing new modesets > on MST connectors that have just been destroyed is rather broken. > There's nothing in the actual DRM DP MST topology helpers that checks > whether or not a connector still exists, instead each DRM driver does > this on it's own, usually by returning NULL from the best_encoder > callback which in turn, causes the atomic commit to fail. > > However, this is wrong in a rather subtle way. If ->best_encoder() > returns NULL, this makes ALL modesets involving the connector fail. This > includes modesets from userspace that would shut off the CRTCs being > used by the connector. Since this results in blocking any changes to a > connector's DPMS prop, it has the sideaffect of preventing legacy > modesetting users from ever disabling a CRTC that was previously enabled > for use in an MST topology. An example of this, where X tries to > change the DPMS property of an MST connector that was just detached from > the system: > > [ 2908.320131] [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] > [CONNECTOR:82:DP-6] > [ 2908.320148] [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] > [CONNECTOR:82:DP-6] status updated from connected to disconnected > [ 2908.320166] [drm:drm_helper_probe_single_connector_modes [drm_kms_helper]] > [CONNECTOR:82:DP-6] disconnected > [ 2908.320193] [drm:drm_mode_object_put.part.2 [drm]] OBJ ID: 111 (1) > [ 2908.320230] [drm:drm_sysfs_hotplug_event [drm]] generating hotplug event > ... > [ 2908.638539] [drm:drm_ioctl [drm]] pid=12928, dev=0xe201, auth=1, > DRM_IOCTL_MODE_SETPROPERTY > [ 2908.638546] [drm:drm_atomic_state_init [drm]] Allocated atomic state > 7155ba49 > [ 2908.638553] [drm:drm_mode_object_get [drm]] OBJ ID: 114 (1) > [ 2908.638560] [drm:drm_mode_object_get [drm]] OBJ ID: 108 (1) > [ 2908.638568] [drm:drm_atomic_get_crtc_state [drm]] Added [CRTC:41:head-0] > 97a6396e state to 7155ba49 > [ 2908.638575] [drm:drm_atomic_add_affected_connectors [drm]] Adding all > current connectors for [CRTC:41:head-0] to 7155ba49 > [ 2908.638582] [drm:drm_mode_object_get [drm]] OBJ ID: 82 (3) > [ 2908.638589] [drm:drm_mode_object_get [drm]] OBJ ID: 82 (4) > [ 2908.638596] [drm:drm_atomic_get_connector_state [drm]] Added > [CONNECTOR:82:DP-6] 87427144 state to 7155ba49 > [ 2908.638603] [drm:drm_atomic_check_only [drm]] checking 7155ba49 > [ 2908.638609] [drm:drm_atomic_helper_check_modeset [drm_kms_helper]] > [CRTC:41:head-0] active changed > [ 2908.638613] [drm:drm_atomic_helper_check_modeset [drm_kms_helper]] > Updating routing for [CONNECTOR:82:DP-6] > [ 2908.638616] [drm:drm_atomic_helper_check_modeset [drm_kms_helper]] No > suitable encoder found for [CONNECTOR:82:DP-6] > [ 2908.638623] [drm:drm_atomic_check_only [drm]] atomic driver check for > 7155ba49 failed: -22 > [ 2908.638630] [drm:drm_atomic_state_default_clear [drm]] Clearing atomic > state 7155ba49 > [ 2908.638637] [drm:drm_mode_object_put.part.2 [drm]] OBJ ID: 82 (4) > [ 2908.638643] [drm:drm_mode_object_put.part.2 [drm]] OBJ ID: 82 (3) > [ 2908.638650] [drm:drm_mode_object_put.part.2 [drm]] OBJ ID: 114 (2) > [ 2908.638656] [drm:drm_mode_object_put.part.2 [drm]] OBJ ID: 108 (2) > [ 2908.638663] [drm:__drm_atomic_state_free [drm]] Freeing atomic state > 7155ba49 > [ 2908.638669] [drm:drm_mode_object_put.part.2 [drm]] OBJ ID: 82 (2) > [ 2908.638676] [drm:drm_ioctl [drm]] pid=12928, ret = -22 > > While this doesn't usually result in any errors that would be obvious to > the user, it does result in us leaving display resources on. This in > turn leads to unwanted sideaffects like inactive GPUs being left on > (usually from the resulting leaked runtime PM ref). > > So, provide an easier way of doing this that doesn't require breaking > ->best_encoder(): add a common drm_dp_mst_connector_atomic_check() > function that DRM drivers can call in order to have CRTC enabling > commits fail automatically if the MST port driving the connector no > longer exists. We'll also be able to expand upon this later as well once > we add MST fallback retraining support. > > Signed-off-by: Lyude Paul > Cc: sta...@vger.kernel.org This does seem like a saner way to handle the case when the MST connector is gone. As this doesn't currently seem to affect amdgpu directly and I therefore might miss something I'll leave the RB to someone else, but you have my Acked-by: Harry Wentland Harry > --- > drivers/gpu/drm/drm_dp_mst_topology.c | 76 +++ > include/drm/drm_dp_mst_helper.h | 3 ++ > 2 files changed, 79 insertions(+) > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c > b/drivers/gpu/drm/drm_dp_mst_topology.c > index 7780567aa669..0162d4bf2549 100644 > --- a/drivers/gpu/drm/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c > @@ -3129,6 +3129,82 @@ static
Re: [Intel-gfx] [PATCH 1/6] drm/dp_mst: Introduce drm_dp_mst_connector_atomic_check()
Hi Lyude,
Thank you for the patch! Perhaps something to improve:
url:
https://github.com/0day-ci/linux/commits/Lyude-Paul/Fix-legacy-DPMS-changes-with-MST/20180919-203434
base: git://anongit.freedesktop.org/drm-intel for-linux-next
smatch warnings:
drivers/gpu/drm/drm_dp_mst_topology.c:3144 drm_dp_mst_connector_still_exists()
error: we previously assumed 'port' could be null (see line 3146)
#
https://github.com/0day-ci/linux/commit/f8df31d5221b9a6da6698d4a37e622253bb17cdc
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout f8df31d5221b9a6da6698d4a37e622253bb17cdc
vim +/port +3144 drivers/gpu/drm/drm_dp_mst_topology.c
3f3353b7 Pandiyan, Dhinakaran 2017-04-20 3131
f8df31d5 Lyude Paul 2018-09-18 3132 static bool
f8df31d5 Lyude Paul 2018-09-18 3133
drm_dp_mst_connector_still_exists(struct drm_connector *connector,
f8df31d5 Lyude Paul 2018-09-18 3134
struct drm_dp_mst_topology_mgr *mgr,
f8df31d5 Lyude Paul 2018-09-18 3135
struct drm_dp_mst_branch *mstb)
f8df31d5 Lyude Paul 2018-09-18 3136 {
f8df31d5 Lyude Paul 2018-09-18 3137 struct drm_dp_mst_port
*port;
f8df31d5 Lyude Paul 2018-09-18 3138 bool exists = false;
f8df31d5 Lyude Paul 2018-09-18 3139
f8df31d5 Lyude Paul 2018-09-18 3140 mstb =
drm_dp_get_validated_mstb_ref(mgr, mstb);
f8df31d5 Lyude Paul 2018-09-18 3141 if (!mstb)
f8df31d5 Lyude Paul 2018-09-18 3142 return false;
f8df31d5 Lyude Paul 2018-09-18 3143
f8df31d5 Lyude Paul 2018-09-18 @3144
list_for_each_entry(port, >ports, next) {
We need to use a different loop iterator, or possibly
list_for_each_entry_safe() because it looks like we're freeing
something. Maybe it's cleanest to do both.
f8df31d5 Lyude Paul 2018-09-18 3145 port =
drm_dp_get_validated_port_ref(mgr, port);
f8df31d5 Lyude Paul 2018-09-18 @3146 if (!port)
f8df31d5 Lyude Paul 2018-09-18 3147
continue;
f8df31d5 Lyude Paul 2018-09-18 3148
f8df31d5 Lyude Paul 2018-09-18 3149 exists =
(port->connector == connector ||
f8df31d5 Lyude Paul 2018-09-18 3150
(port->mstb &&
f8df31d5 Lyude Paul 2018-09-18 3151
drm_dp_mst_connector_still_exists(connector, mgr,
f8df31d5 Lyude Paul 2018-09-18 3152
port->mstb)));
f8df31d5 Lyude Paul 2018-09-18 3153
f8df31d5 Lyude Paul 2018-09-18 3154
drm_dp_put_port(port);
f8df31d5 Lyude Paul 2018-09-18 3155 if (exists)
f8df31d5 Lyude Paul 2018-09-18 3156 break;
f8df31d5 Lyude Paul 2018-09-18 3157 }
f8df31d5 Lyude Paul 2018-09-18 3158
f8df31d5 Lyude Paul 2018-09-18 3159
drm_dp_put_mst_branch_device(mstb);
f8df31d5 Lyude Paul 2018-09-18 3160 return exists;
f8df31d5 Lyude Paul 2018-09-18 3161 }
f8df31d5 Lyude Paul 2018-09-18 3162
---
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Re: [Intel-gfx] [PATCH 1/6] drm/dp_mst: Introduce drm_dp_mst_connector_atomic_check() (fwd)
oh, good catch! will fix and respin in just a little bit
On Wed, 2018-09-19 at 22:38 +0200, Julia Lawall wrote:
> Hello,
>
> I don't think you can update the loop index variable in
> list_for_each_entry, because the mcro uses th index variable to get to the
> next element. Perhaps list_for_each_entry_safe would be more suitable?
>
> julia
>
> -- Forwarded message --
> Date: Thu, 20 Sep 2018 04:30:13 +0800
> From: kbuild test robot
> To: kbu...@01.org
> Cc: Julia Lawall
> Subject: Re: [PATCH 1/6] drm/dp_mst: Introduce
> drm_dp_mst_connector_atomic_check()
>
> CC: kbuild-...@01.org
> In-Reply-To: <20180918230637.20700-2-ly...@redhat.com>
> References: <20180918230637.20700-2-ly...@redhat.com>
> TO: Lyude Paul
> CC: dri-de...@lists.freedesktop.org, nouv...@lists.freedesktop.org,
> intel-gfx@lists.freedesktop.org, amd-...@lists.freedesktop.org
> CC: David Airlie , linux-ker...@vger.kernel.org,
> sta...@vger.kernel.org, Sean Paul
>
> Hi Lyude,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on drm-intel/for-linux-next]
> [also build test WARNING on v4.19-rc4 next-20180919]
> [if your patch is applied to the wrong git tree, please drop us a note to help
> improve the system]
>
> url:
> https://github.com/0day-ci/linux/commits/Lyude-Paul/Fix-legacy-DPMS-changes-with-MST/20180919-203434
> base: git://anongit.freedesktop.org/drm-intel for-linux-next
> :: branch date: 8 hours ago
> :: commit date: 8 hours ago
>
> > > drivers/gpu/drm/drm_dp_mst_topology.c:3144:1-20: iterator with update on
> > > line 3145
>
> #
> https://github.com/0day-ci/linux/commit/f8df31d5221b9a6da6698d4a37e622253bb17cdc
> git remote add linux-review https://github.com/0day-ci/linux
> git remote update linux-review
> git checkout f8df31d5221b9a6da6698d4a37e622253bb17cdc
> vim +3144 drivers/gpu/drm/drm_dp_mst_topology.c
>
> 3f3353b7 Pandiyan, Dhinakaran 2017-04-20 3131
> f8df31d5 Lyude Paul 2018-09-18 3132 static bool
> f8df31d5 Lyude Paul 2018-09-
> 18 3133 drm_dp_mst_connector_still_exists(struct drm_connector *connector,
> f8df31d5 Lyude Paul 2018-09-18 3134
> struct drm_dp_mst_topology_mgr *mgr,
> f8df31d5 Lyude Paul 2018-09-18 3135
> struct drm_dp_mst_branch *mstb)
> f8df31d5 Lyude Paul 2018-09-18 3136 {
> f8df31d5 Lyude Paul 2018-09-18 3137struct drm_dp_mst_port
> *port;
> f8df31d5 Lyude Paul 2018-09-18 3138bool exists = false;
> f8df31d5 Lyude Paul 2018-09-18 3139
> f8df31d5 Lyude Paul 2018-09-18 3140mstb =
> drm_dp_get_validated_mstb_ref(mgr, mstb);
> f8df31d5 Lyude Paul 2018-09-18 3141if (!mstb)
> f8df31d5 Lyude Paul 2018-09-18 3142return false;
> f8df31d5 Lyude Paul 2018-09-18 3143
> f8df31d5 Lyude Paul 2018-09-18 @3144list_for_each_entry(port
> , >ports, next) {
> f8df31d5 Lyude Paul 2018-09-18 @3145port =
> drm_dp_get_validated_port_ref(mgr, port);
> f8df31d5 Lyude Paul 2018-09-18 3146if (!port)
> f8df31d5 Lyude Paul 2018-09-18 3147continue
> ;
> f8df31d5 Lyude Paul 2018-09-18 3148
> f8df31d5 Lyude Paul 2018-09-18 3149exists = (port-
> >connector == connector ||
> f8df31d5 Lyude Paul 2018-09-18 3150 (port-
> >mstb &&
> f8df31d5 Lyude Paul 2018-09-18 3151 drm_d
> p_mst_connector_still_exists(connector, mgr,
> f8df31d5 Lyude Paul 2018-09-18 3152
>
>port->mstb)));
> f8df31d5 Lyude Paul 2018-09-18 3153
> f8df31d5 Lyude Paul 2018-09-18 3154drm_dp_put_port(
> port);
> f8df31d5 Lyude Paul 2018-09-18 3155if (exists)
> f8df31d5 Lyude Paul 2018-09-18 3156break;
> f8df31d5 Lyude Paul 2018-09-18 3157}
> f8df31d5 Lyude Paul 2018-09-18 3158
> f8df31d5 Lyude Paul 2018-09-18 3159drm_dp_put_mst_branch_de
> vice(mstb);
> f8df31d5 Lyude Paul 2018-09-18 3160return exists;
> f8df31d5 Lyude Paul 2018-09-18 3161 }
> f8df31d5 Lyude Paul 2018-09-18 3162
>
> ---
> 0-DAY kernel test infrastructureOpen Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
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Re: [Intel-gfx] [PATCH 1/6] drm/dp_mst: Introduce drm_dp_mst_connector_atomic_check() (fwd)
Hello,
I don't think you can update the loop index variable in
list_for_each_entry, because the mcro uses th index variable to get to the
next element. Perhaps list_for_each_entry_safe would be more suitable?
julia
-- Forwarded message --
Date: Thu, 20 Sep 2018 04:30:13 +0800
From: kbuild test robot
To: kbu...@01.org
Cc: Julia Lawall
Subject: Re: [PATCH 1/6] drm/dp_mst: Introduce
drm_dp_mst_connector_atomic_check()
CC: kbuild-...@01.org
In-Reply-To: <20180918230637.20700-2-ly...@redhat.com>
References: <20180918230637.20700-2-ly...@redhat.com>
TO: Lyude Paul
CC: dri-de...@lists.freedesktop.org, nouv...@lists.freedesktop.org,
intel-gfx@lists.freedesktop.org, amd-...@lists.freedesktop.org
CC: David Airlie , linux-ker...@vger.kernel.org,
sta...@vger.kernel.org, Sean Paul
Hi Lyude,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on v4.19-rc4 next-20180919]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/Lyude-Paul/Fix-legacy-DPMS-changes-with-MST/20180919-203434
base: git://anongit.freedesktop.org/drm-intel for-linux-next
:: branch date: 8 hours ago
:: commit date: 8 hours ago
>> drivers/gpu/drm/drm_dp_mst_topology.c:3144:1-20: iterator with update on
>> line 3145
#
https://github.com/0day-ci/linux/commit/f8df31d5221b9a6da6698d4a37e622253bb17cdc
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout f8df31d5221b9a6da6698d4a37e622253bb17cdc
vim +3144 drivers/gpu/drm/drm_dp_mst_topology.c
3f3353b7 Pandiyan, Dhinakaran 2017-04-20 3131
f8df31d5 Lyude Paul 2018-09-18 3132 static bool
f8df31d5 Lyude Paul 2018-09-18 3133
drm_dp_mst_connector_still_exists(struct drm_connector *connector,
f8df31d5 Lyude Paul 2018-09-18 3134
struct drm_dp_mst_topology_mgr *mgr,
f8df31d5 Lyude Paul 2018-09-18 3135
struct drm_dp_mst_branch *mstb)
f8df31d5 Lyude Paul 2018-09-18 3136 {
f8df31d5 Lyude Paul 2018-09-18 3137 struct drm_dp_mst_port
*port;
f8df31d5 Lyude Paul 2018-09-18 3138 bool exists = false;
f8df31d5 Lyude Paul 2018-09-18 3139
f8df31d5 Lyude Paul 2018-09-18 3140 mstb =
drm_dp_get_validated_mstb_ref(mgr, mstb);
f8df31d5 Lyude Paul 2018-09-18 3141 if (!mstb)
f8df31d5 Lyude Paul 2018-09-18 3142 return false;
f8df31d5 Lyude Paul 2018-09-18 3143
f8df31d5 Lyude Paul 2018-09-18 @3144
list_for_each_entry(port, >ports, next) {
f8df31d5 Lyude Paul 2018-09-18 @3145 port =
drm_dp_get_validated_port_ref(mgr, port);
f8df31d5 Lyude Paul 2018-09-18 3146 if (!port)
f8df31d5 Lyude Paul 2018-09-18 3147
continue;
f8df31d5 Lyude Paul 2018-09-18 3148
f8df31d5 Lyude Paul 2018-09-18 3149 exists =
(port->connector == connector ||
f8df31d5 Lyude Paul 2018-09-18 3150
(port->mstb &&
f8df31d5 Lyude Paul 2018-09-18 3151
drm_dp_mst_connector_still_exists(connector, mgr,
f8df31d5 Lyude Paul 2018-09-18 3152
port->mstb)));
f8df31d5 Lyude Paul 2018-09-18 3153
f8df31d5 Lyude Paul 2018-09-18 3154
drm_dp_put_port(port);
f8df31d5 Lyude Paul 2018-09-18 3155 if (exists)
f8df31d5 Lyude Paul 2018-09-18 3156 break;
f8df31d5 Lyude Paul 2018-09-18 3157 }
f8df31d5 Lyude Paul 2018-09-18 3158
f8df31d5 Lyude Paul 2018-09-18 3159
drm_dp_put_mst_branch_device(mstb);
f8df31d5 Lyude Paul 2018-09-18 3160 return exists;
f8df31d5 Lyude Paul 2018-09-18 3161 }
f8df31d5 Lyude Paul 2018-09-18 3162
---
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