Re: [PATCH] drm/sysfs: Provide per connector control of DRM KMS polling

[Florian Mickler <florian@mickler.org>]

[cc'd chris wilson]

Hi Andy!

On Mon, 20 Sep 2010 19:02:30 -0400
Andy Walls <awalls@md.metrocast.net> wrote:

> BTW, I found that Chris Wilson recently committed a change to inhibit
> all drm connector polling globally for a different reason:
> 
> http://git.kernel.org/?p=linux/kernel/git/airlied/drm-2.6.git;a=commit;h=e58f637bb96d5a0ae0919b9998b891d1ba7e47c9
> 
> That commit message shows a case where the driver decides polling needs
> to happen, but the human knows differently and manual control over
> connector polling mitigates the problem.


On Mon, 20 Sep 2010 17:11:48 -0400
Andy Walls <awalls@md.metrocast.net> wrote:

> On Mon, 2010-09-20 at 11:52 -0700, Greg KH wrote:
> > On Mon, Sep 20, 2010 at 08:59:00AM -0400, Andy Walls wrote:
>  
> > > This change allows the root user to disable (and re-enable) DRM KMS
> > > connector polling on a per connector basis via sysfs, like so:
> > > 
> > >         # cat /sys/class/drm/card0/card0-DVI-D-1/polled
> > >         [hotplug_detectable] connect disconnect
> 
> > You are adding a sysfs file, yet you forgot to add a file in
> > Documentation/ABI.  Please fix that and resend the patch.
> 
> Oops, process failure, sorry.
> Will do.
> 
> Regards,
> Andy
> 

I thought sysfs files should be one thing per file... so, maybe
card0-DVI-D-1/link_status and card0-DVI-D-1/hotplug_detectable with 0/1
content would be easier to manipulate and parse? 

I have to defer to the drm maintainers for the usecases. But how is
having a monitor with a broken edid handled right now? While the output
is connected and used, it probably just stops polling?

cheers,
Flo