Re: [PATCH i-g-t 35/39] lib/vkms: Test changing enabled device planes

["José Expósito" <jose.exposito89@gmail.com>]

Hi Louis,

Thanks a lot for reviewing this series, there were a ton of
patches. I hope they were easy enough to understand :)

I won't have time to look into all of your reviews this week,
but I'll try to at least anwser to this one as I see you are
finding some test failures.

On Fri, Feb 28, 2025 at 09:51:47AM +0100, Louis Chauvet wrote:
> 
> 
> Le 18/02/2025 à 17:50, José Expósito a écrit :
> > Test that, once a VKMS device is enabled, the plane values can't change
> > and that deleting it or the attached CRTCs doesn't change the VKMS
> > device.
> > 
> > Add a function that performs a basic validation checking that the
> > device created matches the expected one.
> > 
> > Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> 
> The next tests don't pass on my VM, can you share details on your setup?
> (kernel branch, architecture)

I'm testing on a QEMU VM (x86_64), using this kernel branch [1], which
is basically [2] + [3].

This is the script I'm using to run the IGT tests:

  $ meson setup build ; ninja -C build && \
     ssh -p 2222 jose@127.0.0.1 -t \
            'cd shared/igt-gpu-tools && \
            sudo modprobe vkms && \
            sudo systemctl isolate multi-user.target && \
            sudo IGT_DEVICE="sys:/sys/devices/platform/vkms" \
                ./build/tests/vkms/vkms_configfs ; \            
            sudo systemctl isolate graphical.target'

Basically, I build in the host and run on the VM by sharing the code
and builds in "shared/igt-gpu-tools" inside the VM.

[1] https://github.com/JoseExposito/linux/tree/patch-vkms-configfs
[2] https://lore.kernel.org/all/20250218101214.5790-1-jose.exposito89@gmail.com/
[3] https://lore.kernel.org/dri-devel/20250225175936.7223-1-jose.exposito89@gmail.com/T/

> > ---
> >   lib/igt_vkms.c             |  27 +++++++
> >   lib/igt_vkms.h             |   1 +
> >   tests/vkms/vkms_configfs.c | 147 +++++++++++++++++++++++++++++++++++++
> >   3 files changed, 175 insertions(+)
> > 
> > diff --git a/lib/igt_vkms.c b/lib/igt_vkms.c
> > index 4c44efec9..3dab7a823 100644
> > --- a/lib/igt_vkms.c
> > +++ b/lib/igt_vkms.c
> > [...]
> > +static void assert_device_config(igt_vkms_config_t *cfg)
> > +{
> > +	drmDevicePtr devices[64];
> > +	drmDevicePtr dev;
> > +	drmModeResPtr res;
> > +	drmModePlaneResPtr plane_res;
> > +	drmModeConnectorPtr connector_res;
> > +	igt_vkms_crtc_config_t *crtc;
> > +	igt_vkms_connector_config_t *connector;
> > +	int n_devices;
> > +	int n_planes = 0;
> > +	int n_crtcs = 0;
> > +	int n_encoders = 0;
> > +	int n_connectors = 0;
> > +	int n_connector_status_cfg[4] = {0};
> > +	int n_connector_status_drm[4] = {0};
> > +	int fd;
> > +
> > +	n_devices = drmGetDevices(devices, ARRAY_SIZE(devices));
> > +
> > +	dev = find_device(cfg->device_name, devices, n_devices);
> > +	igt_assert_f(dev, "Device '%s' not found\n", cfg->device_name);
> > +
> > +	fd = open(dev->nodes[DRM_NODE_PRIMARY], O_RDONLY);
> > +	igt_assert_f(fd >= 0, "Error opening device '%s' at path '%s'\n",
> > +		     cfg->device_name, dev->nodes[DRM_NODE_PRIMARY]);
> > +	igt_assert_f(!drmSetClientCap(fd, DRM_CLIENT_CAP_UNIVERSAL_PLANES, 1),
> > +		     "Error setting DRM_CLIENT_CAP_UNIVERSAL_PLANES\n");
> > +	igt_assert_f(!drmSetClientCap(fd, DRM_CLIENT_CAP_ATOMIC, 1),
> > +		     "Error setting DRM_CLIENT_CAP_ATOMIC\n");
> > +	igt_assert_f(!drmSetClientCap(fd, DRM_CLIENT_CAP_WRITEBACK_CONNECTORS, 1),
> > +		     "Error setting DRM_CLIENT_CAP_WRITEBACK_CONNECTORS\n");
> > +
> > +	res = drmModeGetResources(fd);
> > +	igt_assert_f(res, "Error getting resources\n");
> > +	plane_res = drmModeGetPlaneResources(fd);
> > +	igt_assert_f(plane_res, "Error getting plane resources\n");
> > +
> > +	for (int n = 0; (&cfg->planes[n])->name; n++)
> > +		n_planes++;
> > +
> > +	for (int n = 0; (crtc = &cfg->crtcs[n])->name; n++) {
> > +		n_crtcs++;
> > +
> > +		if (crtc->writeback) {
> > +			n_encoders++;
> > +			n_connectors++;
> > +			n_connector_status_cfg[DRM_MODE_UNKNOWNCONNECTION]++;

I wonder why this is not working for you.

I see in your comment in 39/39 that you are not getting the right numner
of connectors when "crtc->writeback == true", but I'm adding them here.

Could add a log and check if this is actually the problem, please?

Best wishes,
Jose

> > +		}
> > +	}
> > +
> > +	for (int n = 0; (&cfg->encoders[n])->name; n++)
> > +		n_encoders++;
> > +
> > +	for (int n = 0; (connector = &cfg->connectors[n])->name; n++) {
> > +		n_connectors++;
> > +		n_connector_status_cfg[connector->status]++;
> > +	}
> > +
> > +	for (int n = 0; n < res->count_connectors; n++) {
> > +		connector_res = drmModeGetConnectorCurrent(fd,
> > +							   res->connectors[n]);
> > +		n_connector_status_drm[connector_res->connection]++;
> > +		drmModeFreeConnector(connector_res);
> > +	}
> 
> I think the main issue here is something I already observed: you need to
> force probe the connector status (and in this test you really want to do
> it), so you should use `drmModeGetConnector`.
> 
> I just tested, it seems to work, except for the last test about connector
> hotplug (see my review).
> 
> > +
> > +	igt_assert_eq(n_planes, plane_res->count_planes);
> > +	igt_assert_eq(n_crtcs, res->count_crtcs);
> > +	igt_assert_eq(n_encoders, res->count_encoders);
> > +	igt_assert_eq(n_connectors, res->count_connectors);
> > +	igt_assert_eq(n_connector_status_cfg[DRM_MODE_CONNECTED],
> > +		      n_connector_status_drm[DRM_MODE_CONNECTED]);
> > +	igt_assert_eq(n_connector_status_cfg[DRM_MODE_DISCONNECTED],
> > +		      n_connector_status_drm[DRM_MODE_DISCONNECTED]);
> > +	igt_assert_eq(n_connector_status_cfg[DRM_MODE_UNKNOWNCONNECTION],
> > +		      n_connector_status_drm[DRM_MODE_UNKNOWNCONNECTION]);
> 
> ^ Fails on those asserts
> 
> > +
> > +	drmModeFreePlaneResources(plane_res);
> > +	drmModeFreeResources(res);
> > +	close(fd);
> > +	drmFreeDevices(devices, n_devices);
> > +}
> > +
> >   /**
> >    * SUBTEST: device-default-files
> >    * Description: Test that creating a VKMS device creates the default files and
> > @@ -1414,6 +1497,69 @@ static void test_enable_too_many_connectors(void)
> >   	igt_vkms_device_destroy(dev);
> >   }
> > +/**
> > + * SUBTEST: enabled-plane-cannot-change
> > + * Description: Test that, once a VKMS device is enabled, the plane values can't
> > + *              change and that deleting it or the attached CRTCs doesn't change
> > + *              the VKMS device.
> > + */
> > +
> > +static void test_enabled_plane_cannot_change(void)
> > +{
> > +	igt_vkms_t *dev;
> > +
> > +	igt_vkms_config_t cfg = {
> > +		.device_name = __func__,
> > +		.planes = {
> > +			{
> > +				.name = "plane0",
> > +				.type = DRM_PLANE_TYPE_PRIMARY,
> > +				.possible_crtcs = { "crtc0"},
> > +			},
> > +			{
> > +				.name = "plane1",
> > +				.type = DRM_PLANE_TYPE_PRIMARY,
> > +				.possible_crtcs = { "crtc1"},
> > +			},
> > +		},
> > +		.crtcs = {
> > +			{ .name = "crtc0" },
> > +			{ .name = "crtc1" },
> > +		},
> > +		.encoders = {
> > +			{ .name = "encoder0", .possible_crtcs = { "crtc0" } },
> > +			{ .name = "encoder1", .possible_crtcs = { "crtc1" } },
> > +		},
> > +		.connectors = {
> > +			{
> > +				.name = "connector0",
> > +				.possible_encoders = { "encoder0", "encoder1" },
> > +			},
> > +		},
> > +	};
> > +
> > +	dev = igt_vkms_device_create_from_config(&cfg);
> > +	igt_assert(dev);
> > +
> > +	igt_vkms_device_set_enabled(dev, true);
> > +	igt_assert(igt_vkms_device_is_enabled(dev));
> > +	assert_device_config(&cfg);
> > +
> > +	/* Try to change values */
> > +	igt_vkms_plane_set_type(dev, "plane0", DRM_PLANE_TYPE_OVERLAY);
> > +	igt_assert_eq(igt_vkms_plane_get_type(dev, "plane0"),
> > +		      DRM_PLANE_TYPE_PRIMARY);
> > +
> > +	igt_assert(!igt_vkms_plane_attach_crtc(dev, "plane0", "crtc1"));
> > +
> > +	/* Deleting pipeline items doesn't affect the device */
> > +	igt_assert(igt_vkms_plane_detach_crtc(dev, "plane0", "crtc0"));
> > +	igt_assert(igt_vkms_device_remove_plane(dev, "plane0"));
> > +	assert_device_config(&cfg);
> > +
> > +	igt_vkms_device_destroy(dev);
> > +}
> > +
> >   igt_main
> >   {
> >   	struct {
> > @@ -1451,6 +1597,7 @@ igt_main
> >   		{ "enable-crtc-no-encoder", test_enable_crtc_no_encoder },
> >   		{ "enable-no-connectors", test_enable_no_connectors },
> >   		{ "enable-too-many-connectors", test_enable_too_many_connectors },
> > +		{ "enabled-plane-cannot-change", test_enabled_plane_cannot_change },
> >   	};
> >   	igt_fixture {
> 
> -- 
> Louis Chauvet, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
> 
>