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

From: Florian Mickler
Date: Wed Sep 22 2010 - 05:44:27 EST


[cc'd chris wilson]

Hi Andy!

On Mon, 20 Sep 2010 19:02:30 -0400
Andy Walls <awalls@xxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxx> 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




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