[igt-dev] [PATCH i-g-t v2] tests/kms_chamelium: Make sure we wait for each connectors' hotplug event

[Ser, Simon]

On Thu, 2019-05-09 at 11:56 -0400, Lyude Paul wrote:
> I'm in support of this as well, we really could use better hotplug events.
> Feel free to cc patches to me for review :)

Any idea(s) how the API would look like?

> On Thu, 2019-05-09 at 14:24 +0200, Paul Kocialkowski wrote:
> > Hi,
> > 
> > On Thu, 2019-05-09 at 15:08 +0300, Imre Deak wrote:
> > > On Thu, May 09, 2019 at 09:25:41AM +0200, Paul Kocialkowski wrote:
> > > > On Wed, 2019-05-08 at 11:24 +0300, Imre Deak wrote:
> > > > > After scheduling an HPD toggle event, make sure that we wait for the
> > > > > hotplug event for each connector that may be sent by the driver.
> > > > > 
> > > > > Depending on the scheduling there could be 1 event or as many events
> > > > > as
> > > > > connectors we scheduled an HPD toggle event on, depending on the
> > > > > timing.
> > > > > So if we don't yet see the expected connector state on a given
> > > > > connector
> > > > > try to wait for an additional hotplug event and reprobe/recheck the
> > > > > state.
> > > > 
> > > > This changes makes good sense to me, so:
> > > > 
> > > > Reviewed-By: Paul Kocialkowski <paul.kocialkowski at bootlin.com>
> > > > 
> > > > And it brings back hard feelings about the hotplug interface we have
> > > > today...
> > > 
> > > Yes, I was surprised too not find any way to identify which connector(s)
> > > the hotplug event is associated with. We discussed with Ville if it'd
> > > make sense to add a connector ID map to the uevent, but not sure if it'd
> > > be useful outside of this test, or how that would align with Chris'
> > > connector probe state generation idea.
> > 
> > Either way, I'm definitely in favor of having something more reliable
> > to expose to userspace. Having something to correlate each event to one
> > (or more) connector(s) sounds good to me.
> > 
> > And I think there is a general need for this, it's not just IGT.
> > 
> > Currently, every userspace application using DRM has to do a full
> > reprobe once a hotplug uevent is received, which is really not optimal.
> > If an entry identifying the connector was also provided, userspace
> > could only reprobe that connector. The step after that would be having
> > the indication of whether the connector was connected or disconnected
> > directly in uevent too, so that no probing needs to be done at all when
> > a given connector is disconnected.
> > 
> > Anyway, if you're interested in the idea and that Ville and Chris are
> > in favor, I really think it would be worth fixing that. And we'd only
> > be adding new elements to uevent, so that would stay backward-
> > compatible too.
> > 
> > Cheers,
> > 
> > Paul
> > 
> > > > > v2:
> > > > > - s/igt_assert(x >= y)/igt_assert_lte(y, x)/ to see the actual limits
> > > > > in
> > > > >   the debugging output. (Lyude)
> > > > > 
> > > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110534
> > > > > Cc: Paul Kocialkowski <paul.kocialkowski at bootlin.com>
> > > > > Cc: Lyude Paul <lyude at redhat.com>
> > > > > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > > > > Reviewed-by: Lyude Paul <lyude at redhat.com>
> > > > > ---
> > > > >  tests/kms_chamelium.c | 45 +++++++++++++++++++++++++++++++++++++-----
> > > > > -
> > > > >  1 file changed, 39 insertions(+), 6 deletions(-)
> > > > > 
> > > > > diff --git a/tests/kms_chamelium.c b/tests/kms_chamelium.c
> > > > > index 714e5e06..502f1efa 100644
> > > > > --- a/tests/kms_chamelium.c
> > > > > +++ b/tests/kms_chamelium.c
> > > > > @@ -284,11 +284,32 @@ test_edid_read(data_t *data, struct
> > > > > chamelium_port *port,
> > > > >  	drmModeFreeConnector(connector);
> > > > >  }
> > > > >  
> > > > > +/* Wait for hotplug and return the remaining time left from timeout
> > > > > */
> > > > > +static bool wait_for_hotplug(struct udev_monitor *mon, int *timeout)
> > > > > +{
> > > > > +	struct timespec start, end;
> > > > > +	int elapsed;
> > > > > +	bool detected;
> > > > > +
> > > > > +	igt_assert_eq(igt_gettime(&start), 0);
> > > > > +	detected = igt_hotplug_detected(mon, *timeout);
> > > > > +	igt_assert_eq(igt_gettime(&end), 0);
> > > > > +
> > > > > +	elapsed = igt_time_elapsed(&start, &end);
> > > > > +	igt_assert_lte(0, elapsed);
> > > > > +	*timeout = max(0, *timeout - elapsed);
> > > > > +
> > > > > +	return detected;
> > > > > +}
> > > > > +
> > > > >  static void
> > > > >  try_suspend_resume_hpd(data_t *data, struct chamelium_port *port,
> > > > >  		       enum igt_suspend_state state, enum
> > > > > igt_suspend_test test,
> > > > >  		       struct udev_monitor *mon, bool connected)
> > > > >  {
> > > > > +	drmModeConnection target_state = connected ?
> > > > > DRM_MODE_DISCONNECTED :
> > > > > +						     DRM_MODE_CONNECTE
> > > > > D;
> > > > > +	int timeout = HOTPLUG_TIMEOUT;
> > > > >  	int delay;
> > > > >  	int p;
> > > > >  
> > > > > @@ -310,17 +331,29 @@ try_suspend_resume_hpd(data_t *data, struct
> > > > > chamelium_port *port,
> > > > >  	}
> > > > >  
> > > > >  	igt_system_suspend_autoresume(state, test);
> > > > > +	igt_assert(wait_for_hotplug(mon, &timeout));
> > > > >  
> > > > > -	igt_assert(igt_hotplug_detected(mon, HOTPLUG_TIMEOUT));
> > > > >  	if (port) {
> > > > > -		igt_assert_eq(reprobe_connector(data, port), connected
> > > > > ?
> > > > > -			      DRM_MODE_DISCONNECTED :
> > > > > DRM_MODE_CONNECTED);
> > > > > +		igt_assert_eq(reprobe_connector(data, port),
> > > > > target_state);
> > > > >  	} else {
> > > > >  		for (p = 0; p < data->port_count; p++) {
> > > > > +			drmModeConnection current_state;
> > > > > +
> > > > >  			port = data->ports[p];
> > > > > -			igt_assert_eq(reprobe_connector(data, port),
> > > > > connected ?
> > > > > -				      DRM_MODE_DISCONNECTED :
> > > > > -				      DRM_MODE_CONNECTED);
> > > > > +			/*
> > > > > +			 * There could be as many hotplug events sent
> > > > > by
> > > > > +			 * driver as connectors we scheduled an HPD
> > > > > toggle on
> > > > > +			 * above, depending on timing. So if we're not
> > > > > seeing
> > > > > +			 * the expected connector state try to wait
> > > > > for an HPD
> > > > > +			 * event for each connector/port.
> > > > > +			 */
> > > > > +			current_state = reprobe_connector(data, port);
> > > > > +			if (p > 0 && current_state != target_state) {
> > > > > +				igt_assert(wait_for_hotplug(mon,
> > > > > &timeout));
> > > > > +				current_state =
> > > > > reprobe_connector(data, port);
> > > > > +			}
> > > > > +
> > > > > +			igt_assert_eq(current_state, target_state);
> > > > >  		}
> > > > >  
> > > > >  		port = NULL;
> > > > -- 
> > > > Paul Kocialkowski, Bootlin
> > > > Embedded Linux and kernel engineering
> > > > https://bootlin.com
> > > >