Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On 02/01/2017 12:52 AM, Daniel Vetter wrote: > On Tue, Jan 31, 2017 at 04:27:14PM -0800, Dave Hansen wrote: >> I added some printk()s all over and gathered a bit more information >> about what's going on. It looks like the display doesn't work until the >> drm connector code cleans up the *old* connector. For some reason, it >> isn't motivated to do that until I go to the console and back. >> >> In this case, the display was connected to DP-4. >> intel_dp_destroy_mst_connector() got called on it when I switched away, >> but drm_connector_cleanup() did not get called. Upon switching back >> DP-3/5/6 get created. One of these *eventually* ends up being >> "enabled", but is not now. When I switch over to the console, >> drm_connector_cleanup() finally gets called on the old connector: DP-4 >> and I can switch back to X and I see one of DP-3/5/6 enabled and working. >> >> Here are some snippets of dmesg interspersed with what I was doing: > > Ok, so the delayed deleting seems to be involved in the bug (and we only > do that since we recently introduced refcounting for hotplugged > connectors). The question is who's getting confused, either kernel or X. > To figure this out, next time things are out of sync, please compare the > output of > > $ xrandr > > with what's reported in /sys/class/drm/*/status: > > $ grep . /sys/class/drm/card0-DP-*/status OK, I collected that 4 times: 1. When everything is OK 2. When the DVI is unplugged 3. When the DVI is re-plugged (no output) 4. After I press Ctrl-Alt-F2 (back to OK) The good vs. bad diff looks like this: --- xdebug.1485980540.start.log 2017-02-01 12:22:20.328242293 -0800 +++ xdebug.1485980621.dvi-replugged.log 2017-02-01 12:23:41.964241982 -0800 @@ -25,15 +25,6 @@ DP2-1 disconnected (normal left inverted right x axis y axis) DP2-2 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm 1920x1200 60.0*+ - 1920x1080 60.0 - 1600x1200 60.0 - 1680x1050 59.9 - 1280x1024 60.0 - 1280x960 60.0 - 1024x768 60.0 - 800x60060.3 - 640x48059.9 - 720x40070.1 DP2-3 disconnected (normal left inverted right x axis y axis) HDMI1 disconnected (normal left inverted right x axis y axis) HDMI2 disconnected (normal left inverted right x axis y axis) @@ -41,5 +32,5 @@ /sys/class/drm/card0-DP-1/status:disconnected /sys/class/drm/card0-DP-2/status:disconnected /sys/class/drm/card0-DP-3/status:disconnected -/sys/class/drm/card0-DP-5/status:connected +/sys/class/drm/card0-DP-4/status:connected /sys/class/drm/card0-DP-6/status:disconnected But it's very interesting that when I unplug the DVI, the xrandr output does not change. Only the /sys/class/drm/.../status does. > Another question: What desktop are you using, and if you unplug a screen, > does that general reconfigure the desktop size to disable that output? The > zombie connector only sticks around as long as someone is still using it > in the screen configuration. As soon as the reconfiguration has happened, > it should go away. You can test this by manually disabling the output when > it's stuck as on: > > $ xrandr --output DP-4 --off Yep, it does the delayed cleanup. The output still shows up in xrandr (as an 8x8 display) at this point, but it can at least be turned back on. xrandr snippet: Screen 0: minimum 8 x 8, current 8 x 8, maximum 32767 x 32767 So, if I do a pair of these: xrandr --output DP-4 --off xrandr --output DP-4 --auto it does bring the display back consistently. Screen 0: minimum 8 x 8, current 1920 x 1200, maximum 32767 x 32767 eDP1 connected (normal left inverted right x axis y axis) 1920x1080 60.0 + 59.9 1680x1050 60.0 59.9 1600x1024 60.2 1400x1050 60.0 1600x900 60.0 1280x1024 60.0 1440x900 59.9 1280x960 60.0 1368x768 60.0 1360x768 59.8 60.0 1152x864 60.0 1280x720 60.0 1024x768 60.0 1024x576 60.0 960x54060.0 800x60060.3 56.2 864x48660.0 640x48059.9 720x40560.0 640x36060.0 DP1 disconnected (normal left inverted right x axis y axis) DP2 disconnected (normal left inverted right x axis y axis) DP2-1 disconnected (normal left inverted right x axis y axis) DP2-2 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm 1920x1200 60.0*+ 1920x1080 60.0 1600x1200 60.0 1680x1050 59.9 1280x1024 60.0 1280x960 60.0 1024x768 60.0 800x60060.3 640x48059.9 720x40070.1 DP2-3 disconnected (normal left inverted right x axis y axis) HDMI1 disconnected (normal left inverted right x axis y axis) HDMI2 disconnected (normal left inverted right x axis y axis) VIRTUAL1 disconnected (normal left inverte
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On Tue, Jan 31, 2017 at 04:27:14PM -0800, Dave Hansen wrote: > I added some printk()s all over and gathered a bit more information > about what's going on. It looks like the display doesn't work until the > drm connector code cleans up the *old* connector. For some reason, it > isn't motivated to do that until I go to the console and back. > > In this case, the display was connected to DP-4. > intel_dp_destroy_mst_connector() got called on it when I switched away, > but drm_connector_cleanup() did not get called. Upon switching back > DP-3/5/6 get created. One of these *eventually* ends up being > "enabled", but is not now. When I switch over to the console, > drm_connector_cleanup() finally gets called on the old connector: DP-4 > and I can switch back to X and I see one of DP-3/5/6 enabled and working. > > Here are some snippets of dmesg interspersed with what I was doing: Ok, so the delayed deleting seems to be involved in the bug (and we only do that since we recently introduced refcounting for hotplugged connectors). The question is who's getting confused, either kernel or X. To figure this out, next time things are out of sync, please compare the output of $ xrandr with what's reported in /sys/class/drm/*/status: $ grep . /sys/class/drm/card0-DP-*/status Another question: What desktop are you using, and if you unplug a screen, does that general reconfigure the desktop size to disable that output? The zombie connector only sticks around as long as someone is still using it in the screen configuration. As soon as the reconfiguration has happened, it should go away. You can test this by manually disabling the output when it's stuck as on: $ xrandr --output DP-4 --off That should result in the delayed cleanup happening when you look at dmesg afterwards. Thanks, Daniel > > Push DVI switch button to switch to other system: > > > [ 6824.562838] drm_dp_destroy_port() kfree(8801ade46800) > > [ 6824.563164] drm_dp_destroy_connector_work() port: 8801ade42000 > > connector: 8801ade46000 > > [ 6824.563178] intel_dp_destroy_mst_connector() connector: 8801ade46000 > > name: DP-3 &name: 8801ade46048 intel_connector: 8801ade46000 > > [ 6824.563186] drm_sysfs_connector_remove() connector: 8801ade46000 > > kdev: 8801a941b400 > > [ 6824.571556] drm_connector_cleanup(8801ade46000)::329 > > connector->registered: 0 cpu: 3 > > [ 6824.571570] drm_connector_cleanup() kfree() connector->name: 'DP-3' > > &name: 8801ade46048 > > [ 6824.571581] drm_dp_free_mst_port() kfree port: 8801ade42000 > > [ 6824.571587] drm_dp_destroy_connector_work() port: 8801ade42800 > > connector: 8801ade47000 > > [ 6824.571594] intel_dp_destroy_mst_connector() connector: 8801ade47000 > > name: DP-4 &name: 8801ade47048 intel_connector: 8801ade47000 > > [ 6824.571601] drm_sysfs_connector_remove() connector: 8801ade47000 > > kdev: 8801a941a000 > > [ 6824.571915] drm_dp_free_mst_port() kfree port: 8801ade42800 > > [ 6824.571925] drm_dp_destroy_connector_work() port: 8801ade40800 > > connector: 8801ade43000 > > [ 6824.571934] intel_dp_destroy_mst_connector() connector: 8801ade43000 > > name: DP-6 &name: 8801ade43048 intel_connector: 8801ade43000 > > [ 6824.571943] drm_sysfs_connector_remove() connector: 8801ade43000 > > kdev: 8801a9419800 > > [ 6824.572091] drm_connector_cleanup(8801ade43000)::329 > > connector->registered: 0 cpu: 3 > > [ 6824.572101] drm_connector_cleanup() kfree() connector->name: 'DP-6' > > &name: 8801ade43048 > > [ 6824.572110] drm_dp_free_mst_branch_device() kfree mstb: 88030ac22600 > > [ 6824.572117] drm_dp_free_mst_port() kfree port: 8801ade40800 > > Push button to switch back: > > > [ 6837.349693] drm_connector_init() connector->name: 'DP-3' &name: > > 88040231d848 > > [ 6837.349894] drm_sysfs_connector_add() connector: 88040231d800 kdev: > > 8801ae99f400 > > [ 6837.352786] drm_connector_init() connector->name: 'DP-5' &name: > > 880402318048 > > [ 6837.352951] drm_sysfs_connector_add() connector: 880402318000 kdev: > > 8801ae99c000 > > [ 6837.353036] drm_connector_init() connector->name: 'DP-6' &name: > > 88040d37f048 > > [ 6837.353154] drm_sysfs_connector_add() connector: 88040d37f000 kdev: > > 8801ae99ec00 > > I can type into the X session, but both screens are blank. When I press > Ctrl-Alt-F2, I get: > > > [ 6850.494310] drm_connector_cleanup(8801ade47000)::329 > > connector->registered: 0 cpu: 1 > > [ 6850.494314] drm_connector_cleanup() kfree() connector->name: 'DP-4' > > &name: 8801ade47048 > > Now I can switch back to X and everything is OK again. -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
I added some printk()s all over and gathered a bit more information about what's going on. It looks like the display doesn't work until the drm connector code cleans up the *old* connector. For some reason, it isn't motivated to do that until I go to the console and back. In this case, the display was connected to DP-4. intel_dp_destroy_mst_connector() got called on it when I switched away, but drm_connector_cleanup() did not get called. Upon switching back DP-3/5/6 get created. One of these *eventually* ends up being "enabled", but is not now. When I switch over to the console, drm_connector_cleanup() finally gets called on the old connector: DP-4 and I can switch back to X and I see one of DP-3/5/6 enabled and working. Here are some snippets of dmesg interspersed with what I was doing: Push DVI switch button to switch to other system: > [ 6824.562838] drm_dp_destroy_port() kfree(8801ade46800) > [ 6824.563164] drm_dp_destroy_connector_work() port: 8801ade42000 > connector: 8801ade46000 > [ 6824.563178] intel_dp_destroy_mst_connector() connector: 8801ade46000 > name: DP-3 &name: 8801ade46048 intel_connector: 8801ade46000 > [ 6824.563186] drm_sysfs_connector_remove() connector: 8801ade46000 kdev: > 8801a941b400 > [ 6824.571556] drm_connector_cleanup(8801ade46000)::329 > connector->registered: 0 cpu: 3 > [ 6824.571570] drm_connector_cleanup() kfree() connector->name: 'DP-3' &name: > 8801ade46048 > [ 6824.571581] drm_dp_free_mst_port() kfree port: 8801ade42000 > [ 6824.571587] drm_dp_destroy_connector_work() port: 8801ade42800 > connector: 8801ade47000 > [ 6824.571594] intel_dp_destroy_mst_connector() connector: 8801ade47000 > name: DP-4 &name: 8801ade47048 intel_connector: 8801ade47000 > [ 6824.571601] drm_sysfs_connector_remove() connector: 8801ade47000 kdev: > 8801a941a000 > [ 6824.571915] drm_dp_free_mst_port() kfree port: 8801ade42800 > [ 6824.571925] drm_dp_destroy_connector_work() port: 8801ade40800 > connector: 8801ade43000 > [ 6824.571934] intel_dp_destroy_mst_connector() connector: 8801ade43000 > name: DP-6 &name: 8801ade43048 intel_connector: 8801ade43000 > [ 6824.571943] drm_sysfs_connector_remove() connector: 8801ade43000 kdev: > 8801a9419800 > [ 6824.572091] drm_connector_cleanup(8801ade43000)::329 > connector->registered: 0 cpu: 3 > [ 6824.572101] drm_connector_cleanup() kfree() connector->name: 'DP-6' &name: > 8801ade43048 > [ 6824.572110] drm_dp_free_mst_branch_device() kfree mstb: 88030ac22600 > [ 6824.572117] drm_dp_free_mst_port() kfree port: 8801ade40800 Push button to switch back: > [ 6837.349693] drm_connector_init() connector->name: 'DP-3' &name: > 88040231d848 > [ 6837.349894] drm_sysfs_connector_add() connector: 88040231d800 kdev: > 8801ae99f400 > [ 6837.352786] drm_connector_init() connector->name: 'DP-5' &name: > 880402318048 > [ 6837.352951] drm_sysfs_connector_add() connector: 880402318000 kdev: > 8801ae99c000 > [ 6837.353036] drm_connector_init() connector->name: 'DP-6' &name: > 88040d37f048 > [ 6837.353154] drm_sysfs_connector_add() connector: 88040d37f000 kdev: > 8801ae99ec00 I can type into the X session, but both screens are blank. When I press Ctrl-Alt-F2, I get: > [ 6850.494310] drm_connector_cleanup(8801ade47000)::329 > connector->registered: 0 cpu: 1 > [ 6850.494314] drm_connector_cleanup() kfree() connector->name: 'DP-4' &name: > 8801ade47048 Now I can switch back to X and everything is OK again. ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On Mon, Jan 30, 2017 at 08:43:17AM -0800, Dave Hansen wrote: > On 01/30/2017 01:12 AM, Daniel Vetter wrote: > > On Thu, Jan 26, 2017 at 12:34:29PM -0800, Dave Hansen wrote: > ... > >> And, yeah, I think it just gets the connected status wrong. The > >> connector is still there. > > > > Hm, I thought I replied here but I didn't: > > - Is this just after boot (and then the connector is stuck forever), or > > starts to happen after suspend/resume, or some other system change like > > that? Or do they just crop up eventually? > > The most consistent thing I do to screw it up is switch systems on my > DVI KVM switch. When I switch back to the system in question, it > doesn't seem to notice the condition. The connectors eventually show up > with random combinations of switching to the console (ctrl-alt-f1) and > back, running xrandr, or running gnome-control-panel and opening the > Displays applet. Hm, so is this a dp mst kvm switch (i.e. do the connectors get hot-added/removed when you plug/unplug that thing)? Or just some other non-mst switch? I was working under the assumption that this is mst still, but I've never seen an mst kvm switch. > I haven't been able to discern any pattern to it. Sometimes just > running xrandr fixes it. Sometimes just opening the control panel. > Others, I have to do it several times. > > I don't think it shows up if I just leave it for a while. > > > - Does this only happen once the connector is destroyed? Please trace > > intel_dp_destroy_mst_connector with something like: > > I'll see if I can gather that. If it's not mst, then don't bother with this for obvious reasons :-) -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On 01/30/2017 01:12 AM, Daniel Vetter wrote: > On Thu, Jan 26, 2017 at 12:34:29PM -0800, Dave Hansen wrote: ... >> And, yeah, I think it just gets the connected status wrong. The >> connector is still there. > > Hm, I thought I replied here but I didn't: > - Is this just after boot (and then the connector is stuck forever), or > starts to happen after suspend/resume, or some other system change like > that? Or do they just crop up eventually? The most consistent thing I do to screw it up is switch systems on my DVI KVM switch. When I switch back to the system in question, it doesn't seem to notice the condition. The connectors eventually show up with random combinations of switching to the console (ctrl-alt-f1) and back, running xrandr, or running gnome-control-panel and opening the Displays applet. I haven't been able to discern any pattern to it. Sometimes just running xrandr fixes it. Sometimes just opening the control panel. Others, I have to do it several times. I don't think it shows up if I just leave it for a while. > - Does this only happen once the connector is destroyed? Please trace > intel_dp_destroy_mst_connector with something like: I'll see if I can gather that. ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On Thu, Jan 26, 2017 at 12:34:29PM -0800, Dave Hansen wrote:
> On 01/25/2017 07:38 AM, Daniel Vetter wrote:
> > On Wed, Jan 25, 2017 at 07:20:45AM -0800, Dave Hansen wrote:
> >> On 01/24/2017 10:21 PM, Daniel Vetter wrote:
> >>> Hi Dave,
> >>>
> >>> Still waiting for your testing results on this one here ...
> >>
> >> It's definitely stable with that patch applied. No more crashes.
> >>
> >> But, it's also definitely having difficulty re-probing to find the
> >> monitor that's attached to the dock in some cases. Whatever is going on
> >> isn't fixed by poking it with xrandr.
> >
> > Is this new? When exactly does this happen? Does the mst sink connector no
> > longer show up, or is the connected/disconnected status all wrong?
>
> It's hard to say whether it's new or not. I *think* it worked better
> before, but it also crashed pretty often, so it's hard to say.
Ok, I guess that's good enough to push at least the crash fix forward.
> And, yeah, I think it just gets the connected status wrong. The
> connector is still there.
Hm, I thought I replied here but I didn't:
- Is this just after boot (and then the connector is stuck forever), or
starts to happen after suspend/resume, or some other system change like
that? Or do they just crop up eventually?
- Does this only happen once the connector is destroyed? Please trace
intel_dp_destroy_mst_connector with something like:
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c
b/drivers/gpu/drm/i915/intel_dp_mst.c
index 38e3ca2f6f18..24ac2d1ce3ad 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -502,6 +502,8 @@ static void intel_dp_destroy_mst_connector(struct
drm_dp_mst_topology_mgr *mgr,
drm_connector_unregister(connector);
+ printk("mst connector getting destroyed: %s\n", connector->name);
+
/* need to nuke the connector */
drm_modeset_lock_all(dev);
intel_connector_remove_from_fbdev(intel_connector);
- If it's not that then something in intel_dp_mst_detect (well, it's
helper implementation drm_dp_mst_detect_port) is probably going wrong.
Cheers, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On 01/25/2017 07:38 AM, Daniel Vetter wrote: > On Wed, Jan 25, 2017 at 07:20:45AM -0800, Dave Hansen wrote: >> On 01/24/2017 10:21 PM, Daniel Vetter wrote: >>> Hi Dave, >>> >>> Still waiting for your testing results on this one here ... >> >> It's definitely stable with that patch applied. No more crashes. >> >> But, it's also definitely having difficulty re-probing to find the >> monitor that's attached to the dock in some cases. Whatever is going on >> isn't fixed by poking it with xrandr. > > Is this new? When exactly does this happen? Does the mst sink connector no > longer show up, or is the connected/disconnected status all wrong? It's hard to say whether it's new or not. I *think* it worked better before, but it also crashed pretty often, so it's hard to say. And, yeah, I think it just gets the connected status wrong. The connector is still there. ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On Wed, Jan 25, 2017 at 07:20:45AM -0800, Dave Hansen wrote: > On 01/24/2017 10:21 PM, Daniel Vetter wrote: > > Hi Dave, > > > > Still waiting for your testing results on this one here ... > > It's definitely stable with that patch applied. No more crashes. > > But, it's also definitely having difficulty re-probing to find the > monitor that's attached to the dock in some cases. Whatever is going on > isn't fixed by poking it with xrandr. Is this new? When exactly does this happen? Does the mst sink connector no longer show up, or is the connected/disconnected status all wrong? -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On 01/24/2017 10:21 PM, Daniel Vetter wrote: > Hi Dave, > > Still waiting for your testing results on this one here ... It's definitely stable with that patch applied. No more crashes. But, it's also definitely having difficulty re-probing to find the monitor that's attached to the dock in some cases. Whatever is going on isn't fixed by poking it with xrandr. ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
Hi Dave,
Still waiting for your testing results on this one here ...
-Daniel
On Thu, Jan 12, 2017 at 05:17:21PM +0100, Daniel Vetter wrote:
> On Thu, Jan 12, 2017 at 05:15:56PM +0100, Daniel Vetter wrote:
> > I was under the misconception that the sysfs dev stuff can be fully
> > set up, and then registered all in one step with device_add. That's
> > true for properties and property groups, but not for parents and child
> > devices. Those must be fully registered before you can register a
> > child.
> >
> > Add a bit of tracking to make sure that asynchronous mst connector
> > hotplugging gets this right. For consistency we rely upon the implicit
> > barriers of the connector->mutex, which is taken anyway, to ensure
> > that at least either the connector or device registration call will
> > work out.
> >
> > Mildly tested since I can't reliably reproduce this on my mst box
> > here.
> >
> > Reported-by: Dave Hansen
> > Cc: Dave Hansen
> > Cc: Chris Wilson
> > Signed-off-by: Daniel Vetter
>
> Cc: sta...@vger.kernel.org
>
> > ---
> > drivers/gpu/drm/drm_connector.c | 3 +++
> > drivers/gpu/drm/drm_drv.c | 4
> > include/drm/drmP.h | 1 +
> > 3 files changed, 8 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_connector.c
> > b/drivers/gpu/drm/drm_connector.c
> > index c75ab242f907..5999cb83d05b 100644
> > --- a/drivers/gpu/drm/drm_connector.c
> > +++ b/drivers/gpu/drm/drm_connector.c
> > @@ -378,6 +378,9 @@ int drm_connector_register(struct drm_connector
> > *connector)
> > {
> > int ret = 0;
> >
> > + if (!connector->dev->registered)
> > + return 0;
> > +
> > mutex_lock(&connector->mutex);
> > if (connector->registered)
> > goto unlock;
> > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > index 7e24103c47f1..cad6df626678 100644
> > --- a/drivers/gpu/drm/drm_drv.c
> > +++ b/drivers/gpu/drm/drm_drv.c
> > @@ -749,6 +749,8 @@ int drm_dev_register(struct drm_device *dev, unsigned
> > long flags)
> > if (ret)
> > goto err_minors;
> >
> > + dev->registered = true;
> > +
> > if (dev->driver->load) {
> > ret = dev->driver->load(dev, flags);
> > if (ret)
> > @@ -796,6 +798,8 @@ void drm_dev_unregister(struct drm_device *dev)
> >
> > drm_lastclose(dev);
> >
> > + dev->registered = false;
> > +
> > if (drm_core_check_feature(dev, DRIVER_MODESET))
> > drm_modeset_unregister_all(dev);
> >
> > diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> > index c537c278a4be..ec105c339347 100644
> > --- a/include/drm/drmP.h
> > +++ b/include/drm/drmP.h
> > @@ -518,6 +518,7 @@ struct drm_device {
> > struct drm_minor *control; /**< Control node */
> > struct drm_minor *primary; /**< Primary node */
> > struct drm_minor *render; /**< Render node */
> > + bool registered;
> >
> > /* currently active master for this device. Protected by master_mutex */
> > struct drm_master *master;
> > --
> > 2.5.5
> >
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On Thu, Jan 12, 2017 at 05:15:56PM +0100, Daniel Vetter wrote: > I was under the misconception that the sysfs dev stuff can be fully > set up, and then registered all in one step with device_add. That's > true for properties and property groups, but not for parents and child > devices. Those must be fully registered before you can register a > child. > > Add a bit of tracking to make sure that asynchronous mst connector > hotplugging gets this right. For consistency we rely upon the implicit > barriers of the connector->mutex, which is taken anyway, to ensure > that at least either the connector or device registration call will > work out. > > Mildly tested since I can't reliably reproduce this on my mst box > here. Hmm, right it should prevent the oops on load. I think we need to control the async dp-mst better and stop it running until we have the device registered, and so if we use in the interim, plonk a WARN_ON on top for -next and try and fix it for realz. (Probably a drm_dp_mst_mgr_register() hook?) Acked-by: Chris Wilson -Chris -- Chris Wilson, Intel Open Source Technology Centre ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH] drm: Don't race connector registration
On Thu, Jan 12, 2017 at 05:15:56PM +0100, Daniel Vetter wrote:
> I was under the misconception that the sysfs dev stuff can be fully
> set up, and then registered all in one step with device_add. That's
> true for properties and property groups, but not for parents and child
> devices. Those must be fully registered before you can register a
> child.
>
> Add a bit of tracking to make sure that asynchronous mst connector
> hotplugging gets this right. For consistency we rely upon the implicit
> barriers of the connector->mutex, which is taken anyway, to ensure
> that at least either the connector or device registration call will
> work out.
>
> Mildly tested since I can't reliably reproduce this on my mst box
> here.
>
> Reported-by: Dave Hansen
> Cc: Dave Hansen
> Cc: Chris Wilson
> Signed-off-by: Daniel Vetter
Cc: sta...@vger.kernel.org
> ---
> drivers/gpu/drm/drm_connector.c | 3 +++
> drivers/gpu/drm/drm_drv.c | 4
> include/drm/drmP.h | 1 +
> 3 files changed, 8 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index c75ab242f907..5999cb83d05b 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -378,6 +378,9 @@ int drm_connector_register(struct drm_connector
> *connector)
> {
> int ret = 0;
>
> + if (!connector->dev->registered)
> + return 0;
> +
> mutex_lock(&connector->mutex);
> if (connector->registered)
> goto unlock;
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 7e24103c47f1..cad6df626678 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -749,6 +749,8 @@ int drm_dev_register(struct drm_device *dev, unsigned
> long flags)
> if (ret)
> goto err_minors;
>
> + dev->registered = true;
> +
> if (dev->driver->load) {
> ret = dev->driver->load(dev, flags);
> if (ret)
> @@ -796,6 +798,8 @@ void drm_dev_unregister(struct drm_device *dev)
>
> drm_lastclose(dev);
>
> + dev->registered = false;
> +
> if (drm_core_check_feature(dev, DRIVER_MODESET))
> drm_modeset_unregister_all(dev);
>
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index c537c278a4be..ec105c339347 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -518,6 +518,7 @@ struct drm_device {
> struct drm_minor *control; /**< Control node */
> struct drm_minor *primary; /**< Primary node */
> struct drm_minor *render; /**< Render node */
> + bool registered;
>
> /* currently active master for this device. Protected by master_mutex */
> struct drm_master *master;
> --
> 2.5.5
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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[Intel-gfx] [PATCH] drm: Don't race connector registration
I was under the misconception that the sysfs dev stuff can be fully
set up, and then registered all in one step with device_add. That's
true for properties and property groups, but not for parents and child
devices. Those must be fully registered before you can register a
child.
Add a bit of tracking to make sure that asynchronous mst connector
hotplugging gets this right. For consistency we rely upon the implicit
barriers of the connector->mutex, which is taken anyway, to ensure
that at least either the connector or device registration call will
work out.
Mildly tested since I can't reliably reproduce this on my mst box
here.
Reported-by: Dave Hansen
Cc: Dave Hansen
Cc: Chris Wilson
Signed-off-by: Daniel Vetter
---
drivers/gpu/drm/drm_connector.c | 3 +++
drivers/gpu/drm/drm_drv.c | 4
include/drm/drmP.h | 1 +
3 files changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index c75ab242f907..5999cb83d05b 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -378,6 +378,9 @@ int drm_connector_register(struct drm_connector *connector)
{
int ret = 0;
+ if (!connector->dev->registered)
+ return 0;
+
mutex_lock(&connector->mutex);
if (connector->registered)
goto unlock;
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 7e24103c47f1..cad6df626678 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -749,6 +749,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long
flags)
if (ret)
goto err_minors;
+ dev->registered = true;
+
if (dev->driver->load) {
ret = dev->driver->load(dev, flags);
if (ret)
@@ -796,6 +798,8 @@ void drm_dev_unregister(struct drm_device *dev)
drm_lastclose(dev);
+ dev->registered = false;
+
if (drm_core_check_feature(dev, DRIVER_MODESET))
drm_modeset_unregister_all(dev);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index c537c278a4be..ec105c339347 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -518,6 +518,7 @@ struct drm_device {
struct drm_minor *control; /**< Control node */
struct drm_minor *primary; /**< Primary node */
struct drm_minor *render; /**< Render node */
+ bool registered;
/* currently active master for this device. Protected by master_mutex */
struct drm_master *master;
--
2.5.5
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