[PATCH] drm: Return -ENOTSUPP in drm_setclientcap() when driver do not support KMS

[Souza, Jose]

On Fri, 2018-09-14 at 09:15 +0100, Chris Wilson wrote:
> Quoting José Roberto de Souza (2018-09-13 23:13:41)
> > All DRM_CLIENT capabilities are tied to KMS support, so returning
> > -ENOTSUPP when KMS is not supported.
> 
> The posix errno is ENOTSUP (ENOTSUPP is internal). Now since we have
> no
> ENOTSUP in the uapi, I've switched to using EOPNOTSUP as that is
> documented to have the same value as ENOTSUP under Linux. (At least
> until somebody decided to make ENOTSUP unique.)

Oh thanks, I have copied it from drm_getcap() and did not notice.

> 
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/drm_ioctl.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_ioctl.c
> > b/drivers/gpu/drm/drm_ioctl.c
> > index 6b4a633b4240..842423fe9762 100644
> > --- a/drivers/gpu/drm/drm_ioctl.c
> > +++ b/drivers/gpu/drm/drm_ioctl.c
> > @@ -306,6 +306,9 @@ drm_setclientcap(struct drm_device *dev, void
> > *data, struct drm_file *file_priv)
> >  {
> >         struct drm_set_client_cap *req = data;
> >  
> > +       if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > +               return -ENOTSUPP;
> 
> The wider question though is client cap restricted to modesetting
> capabilities? Or should each case include a check like
> DRM_CLIENT_CAP_ATOMIC.

Well all of those:

DRM_CLIENT_CAP_STEREO_3D
DRM_CLIENT_CAP_UNIVERSAL_PLANES
DRM_CLIENT_CAP_ATOMIC
DRM_CLIENT_CAP_ASPECT_RATIO
DRM_CLIENT_CAP_WRITEBACK_CONNECTORS

are just usefull with KMS.


> -Chris