On Wed, Oct 29, 2025 at 03:36:42PM +0100, Louis Chauvet wrote: > As planes can have a name in DRM, prepare VKMS to configure it using > ConfigFS. > > Signed-off-by: Louis Chauvet <[email protected]> > --- > drivers/gpu/drm/vkms/vkms_config.c | 4 ++++ > drivers/gpu/drm/vkms/vkms_config.h | 26 ++++++++++++++++++++++++++ > drivers/gpu/drm/vkms/vkms_drv.h | 5 +++-- > drivers/gpu/drm/vkms/vkms_output.c | 6 +----- > drivers/gpu/drm/vkms/vkms_plane.c | 6 ++++-- > 5 files changed, 38 insertions(+), 9 deletions(-) > > diff --git a/drivers/gpu/drm/vkms/vkms_config.c > b/drivers/gpu/drm/vkms/vkms_config.c > index 858bec2d1312..bfafb5d2504d 100644 > --- a/drivers/gpu/drm/vkms/vkms_config.c > +++ b/drivers/gpu/drm/vkms/vkms_config.c > @@ -352,6 +352,8 @@ static int vkms_config_show(struct seq_file *m, void > *data) > seq_puts(m, "plane:\n"); > seq_printf(m, "\ttype=%s\n", > > drm_get_plane_type_name(vkms_config_plane_get_type(plane_cfg))); > + seq_printf(m, "\tname=%s\n", > + vkms_config_plane_get_name(plane_cfg));
I discovered this while working on some basic IGT tests to validate your changes. I think that this triggers undefined behavior. printf() and friends expect a non NULL value for %s: https://stackoverflow.com/a/11589479 In my Fedora system, this prints "name=(null)", instead of an empty string. The same happens with the ConfigFS API: $ cat /sys/kernel/config/vkms/test_plane_default_values/planes/plane0/name (null) We'd need to return in both places an empty string instead. > } > > vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) { > @@ -392,6 +394,7 @@ struct vkms_config_plane *vkms_config_create_plane(struct > vkms_config *config) > > plane_cfg->config = config; > vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_OVERLAY); > + vkms_config_plane_set_name(plane_cfg, NULL); > xa_init_flags(&plane_cfg->possible_crtcs, XA_FLAGS_ALLOC); > > list_add_tail(&plane_cfg->link, &config->planes); > @@ -404,6 +407,7 @@ void vkms_config_destroy_plane(struct vkms_config_plane > *plane_cfg) > { > xa_destroy(&plane_cfg->possible_crtcs); > list_del(&plane_cfg->link); > + kfree_const(plane_cfg->name); > kfree(plane_cfg); > } > EXPORT_SYMBOL_IF_KUNIT(vkms_config_destroy_plane); > diff --git a/drivers/gpu/drm/vkms/vkms_config.h > b/drivers/gpu/drm/vkms/vkms_config.h > index 4c8d668e7ef8..57342db5795a 100644 > --- a/drivers/gpu/drm/vkms/vkms_config.h > +++ b/drivers/gpu/drm/vkms/vkms_config.h > @@ -35,6 +35,7 @@ struct vkms_config { > * > * @link: Link to the others planes in vkms_config > * @config: The vkms_config this plane belongs to > + * @name: Name of the plane > * @type: Type of the plane. The creator of configuration needs to ensures > that > * at least one primary plane is present. > * @possible_crtcs: Array of CRTCs that can be used with this plane > @@ -47,6 +48,7 @@ struct vkms_config_plane { > struct list_head link; > struct vkms_config *config; > > + const char *name; > enum drm_plane_type type; > struct xarray possible_crtcs; > > @@ -288,6 +290,30 @@ vkms_config_plane_set_type(struct vkms_config_plane > *plane_cfg, > plane_cfg->type = type; > } > > +/** > + * vkms_config_plane_set_name() - Set the plane name > + * @plane_cfg: Plane to set the name to > + * @name: New plane name. The name is copied. > + */ > +static inline void > +vkms_config_plane_set_name(struct vkms_config_plane *plane_cfg, > + const char *name) > +{ > + if (plane_cfg->name) > + kfree_const(plane_cfg->name); > + plane_cfg->name = kstrdup_const(name, GFP_KERNEL); > +} > + > +/** > + * vkms_config_plane_get_name - Get the plane name > + * @plane_cfg: Plane to get the name from > + */ > +static inline const char * > +vkms_config_plane_get_name(const struct vkms_config_plane *plane_cfg) > +{ > + return plane_cfg->name; > +} > + > /** > * vkms_config_plane_attach_crtc - Attach a plane to a CRTC > * @plane_cfg: Plane to attach > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h > index db260df1d4f6..9ad286f043b5 100644 > --- a/drivers/gpu/drm/vkms/vkms_drv.h > +++ b/drivers/gpu/drm/vkms/vkms_drv.h > @@ -225,6 +225,7 @@ struct vkms_output { > }; > > struct vkms_config; > +struct vkms_config_plane; > > /** > * struct vkms_device - Description of a VKMS device > @@ -298,10 +299,10 @@ int vkms_output_init(struct vkms_device *vkmsdev); > * vkms_plane_init() - Initialize a plane > * > * @vkmsdev: VKMS device containing the plane > - * @type: type of plane to initialize > + * @config: plane configuration > */ > struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev, > - enum drm_plane_type type); > + struct vkms_config_plane *config); > > /* CRC Support */ > const char *const *vkms_get_crc_sources(struct drm_crtc *crtc, > diff --git a/drivers/gpu/drm/vkms/vkms_output.c > b/drivers/gpu/drm/vkms/vkms_output.c > index 2ee3749e2b28..22208d02afa4 100644 > --- a/drivers/gpu/drm/vkms/vkms_output.c > +++ b/drivers/gpu/drm/vkms/vkms_output.c > @@ -19,11 +19,7 @@ int vkms_output_init(struct vkms_device *vkmsdev) > return -EINVAL; > > vkms_config_for_each_plane(vkmsdev->config, plane_cfg) { > - enum drm_plane_type type; > - > - type = vkms_config_plane_get_type(plane_cfg); > - > - plane_cfg->plane = vkms_plane_init(vkmsdev, type); > + plane_cfg->plane = vkms_plane_init(vkmsdev, plane_cfg); > if (IS_ERR(plane_cfg->plane)) { > DRM_DEV_ERROR(dev->dev, "Failed to init vkms plane\n"); > return PTR_ERR(plane_cfg->plane); > diff --git a/drivers/gpu/drm/vkms/vkms_plane.c > b/drivers/gpu/drm/vkms/vkms_plane.c > index e592e47a5736..73180cbb78b1 100644 > --- a/drivers/gpu/drm/vkms/vkms_plane.c > +++ b/drivers/gpu/drm/vkms/vkms_plane.c > @@ -9,6 +9,7 @@ > #include <drm/drm_gem_atomic_helper.h> > #include <drm/drm_gem_framebuffer_helper.h> > > +#include "vkms_config.h" > #include "vkms_drv.h" > #include "vkms_formats.h" > > @@ -217,7 +218,7 @@ static const struct drm_plane_helper_funcs > vkms_plane_helper_funcs = { > }; > > struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev, > - enum drm_plane_type type) > + struct vkms_config_plane *config) > { > struct drm_device *dev = &vkmsdev->drm; > struct vkms_plane *plane; > @@ -225,7 +226,8 @@ struct vkms_plane *vkms_plane_init(struct vkms_device > *vkmsdev, > plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 0, > &vkms_plane_funcs, > vkms_formats, > ARRAY_SIZE(vkms_formats), > - NULL, type, NULL); > + NULL, > vkms_config_plane_get_type(config), > + vkms_config_plane_get_name(config)); > if (IS_ERR(plane)) > return plane; > > > -- > 2.51.0 >
