On Fri, Feb 10, 2017 at 09:29:07AM -0700, Shuah Khan wrote: > On 02/03/2017 01:06 AM, Daniel Vetter wrote: > > On Thu, Feb 02, 2017 at 10:25:44AM -0700, Shuah Khan wrote: > >> On 02/02/2017 01:32 AM, Jani Nikula wrote: > >>> On Thu, 02 Feb 2017, Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> wrote: > >>>> Change drm_helper_probe_single_connector_modes() to print an error to > >>>> report connector disconnected status instead of a debug message. > >>>> > >>>> When this condition occurs, application doesn't know the real error and > >>>> reports it as driver lacking support for mode setting. Change it to an > >>>> error to make it easier to debug. > >>> > >>> Please explain what makes this condition an error. Connectors get > >>> connected and disconnected, business as usual, why should this be an > >>> error? > >>> > >>> BR, > >>> Jani. > >> > >> Disconnecting connector itself isn't an error. When user-space tries > >> to access it, it would be useful to report the status that the connector > >> is disconnected. > >> > >> I use embedded system(s) that don't like it when HDMI is hot added or > >> removed. Also, because of return power, it is safer to disconnect HDMI > >> and then apply power to the board. It chased a few libdrm and user-space > >> dead ends before I enabled drm debug and was able to fix the real issue, > >> which is a disconnected cable. > >> > >> User-space prints rather confusing messages as it doesn't really know > >> the disconnected status as it isn't returned to it. > >> > >> I figured it might be a good idea to at least print a message and this can > >> be a notice or info instead of an error. I do think its is worth while in > >> some cases. > > > > This sounds like a very specific use-case you have here, and it can easily > > be supported by a small deamon in userspace (only on debug builds ofc) > > that tell you that someone unplugged the screen when it shouldn't have > > been. > > drm_helper_probe_single_connector_modes() finds the condition and doesn't > have a means to return it to the user-space. Erhm, we send out the uevent for this, and userspace can react. If that's not working, then we need to fix this bug, not add more uapi interfaces on top ... -Daniel > > Instead of error or debug message, would it be useful to add a trace event > to report status of connector to drm_helper_probe_single_connector_modes() > Trace could be triggered as needed and turned off. > > Please let me know what you think of this idea? If it sounds useful, I can > add it. > > > > > Because upstream runs also on non-embedded systems, where unplugging is > > normal, and we definitely don't want to spam dmesg. > > -Daniel > > > > thanks, > -- Shuah > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
