[Intel-gfx] [PATCH v2] drm/i915: Reject modeset when the same digital port is used more than once

[Ville Syrjälä]

On Tue, Dec 02, 2014 at 12:17:28PM +0000, Chris Wilson wrote:
> On Tue, Dec 02, 2014 at 02:10:46PM +0200, ville.syrjala at linux.intel.com wrote:
> > +	if (!check_digital_port_conflicts(dev)) {
> 
> Being picky:
> 
> if not check digital port for conflicts, report error.
> 
> It reads backwards. Perhaps 
> 
> if (conflicting_digital_port_config(dev)) return -EINVAL;

I just followed the pattern established by check_encoder_cloning(). Should
probably rename both if we go down that path.

> 
> > +		DRM_DEBUG_KMS("rejecting conflicting digital port configuration\n");
> > +		return ERR_PTR(-EINVAL);
> > +	}
> 
> Regarding getting more information back to the user about the error
> message, we could with have a connector/crtc property, a procfs file or
> an ioctl to grab a string describing the last error. A LastError
> property blob might be the most convenient. Though I am not sure how
> outlandish this idea is.

Yeah somehow passing a string to userland might be nice for the user. But
I don't think we should start matching such strings in tests, so that
wouldn't help kms_setmode figure out if it just tried something that was
supposed to work or not.

-- 
Ville Syrjälä
Intel OTC