[RFC 1/5] drm: Add HDMI 2.0+ features exposing knob

[Daniel Vetter]

On Thu, Mar 23, 2017 at 10:44:16AM +0000, Jose Abreu wrote:
> Hi Daniel,
> 
> 
> On 23-03-2017 07:22, Daniel Vetter wrote:
> > On Wed, Mar 22, 2017 at 05:35:57PM +0000, Jose Abreu wrote:
> >> We can't expect userspace to have full support for all HDMI 2.0+
> >> features. Instead of expecting/waiting for userspace to support
> >> the new features add a knob, much like the stereo knob, so that
> >> DRM core will only expose the features when asked too.
> >>
> >> Signed-off-by: Jose Abreu <joabreu at synopsys.com>
> >> Cc: Carlos Palminha <palminha at synopsys.com>
> >> Cc: dri-devel at lists.freedesktop.org
> >> ---
> >>  drivers/gpu/drm/drm_ioctl.c | 5 +++++
> >>  include/drm/drm_file.h      | 8 ++++++++
> >>  include/uapi/drm/drm.h      | 7 +++++++
> >>  3 files changed, 20 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> >> index a7c61c2..2430e2e 100644
> >> --- a/drivers/gpu/drm/drm_ioctl.c
> >> +++ b/drivers/gpu/drm/drm_ioctl.c
> >> @@ -318,6 +318,11 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
> >>  		file_priv->atomic = req->value;
> >>  		file_priv->universal_planes = req->value;
> >>  		break;
> >> +	case DRM_CLIENT_CAP_HDMI2:
> >> +		if (req->value > 1)
> >> +			return -EINVAL;
> >> +		file_priv->hdmi2_allowed = req->value;
> > Needs some userspace to make use of this (like the -modesetting x.org
> > driver).
> > -Daniel
> 
> I see your point but shouldn't this be merged before actually
> starting to work in userspace?

No, see

https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#open-source-userspace-requirements

for reasons behind this and the precise flow.

Cheers, Daniel

> 
> Best regards,
> Jose Miguel Abreu
> 
> >
> >> +		break;
> >>  	default:
> >>  		return -EINVAL;
> >>  	}
> >> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> >> index 5dd27ae..7b97d85 100644
> >> --- a/include/drm/drm_file.h
> >> +++ b/include/drm/drm_file.h
> >> @@ -192,6 +192,14 @@ struct drm_file {
> >>  	unsigned is_master:1;
> >>  
> >>  	/**
> >> +	 * @hdmi2_allowed:
> >> +	 *
> >> +	 * True if client understands HDMI 2.0+ features like, for example,
> >> +	 * extended aspect ratios
> >> +	 */
> >> +	unsigned hdmi2_allowed:1;
> >> +
> >> +	/**
> >>  	 * @master:
> >>  	 *
> >>  	 * Master this node is currently associated with. Only relevant if
> >> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> >> index b2c5284..9e25138 100644
> >> --- a/include/uapi/drm/drm.h
> >> +++ b/include/uapi/drm/drm.h
> >> @@ -678,6 +678,13 @@ struct drm_get_cap {
> >>   */
> >>  #define DRM_CLIENT_CAP_ATOMIC	3
> >>  
> >> +/**
> >> + * DRM_CLIENT_CAP_HDMI2
> >> + *
> >> + * If set to 1, the DRM core will expose HDMI 2.0+ features to userspace
> >> + */
> >> +#define DRM_CLIENT_CAP_HDMI2	4
> >> +
> >>  /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
> >>  struct drm_set_client_cap {
> >>  	__u64 capability;
> >> -- 
> >> 1.9.1
> >>
> >>
> >> _______________________________________________
> >> dri-devel mailing list
> >> dri-devel at lists.freedesktop.org
> >> https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.freedesktop.org_mailman_listinfo_dri-2Ddevel&d=DwIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=4lBpQovdR7O8jeC7mV8SX9xvTypMtV8CBDEDg3bGgzw&s=h-gqFlO62i53pir0j2lJ-upE_bXQxhn3BK1nhdxoB6Y&e= 
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch