linux-kernel - Re: [PATCH v4 2/8] drm/nouveau: Enable polling even if we have runtime PM

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Date:   Thu, 02 Aug 2018 15:37:12 -0400
From:   Lyude Paul <lyude@...hat.com>
To:     Lukas Wunner <lukas@...ner.de>
Cc:     nouveau@...ts.freedesktop.org,
        Peter Ujfalusi <peter.ujfalusi@...com>, stable@...r.kernel.org,
        Ben Skeggs <bskeggs@...hat.com>,
        David Airlie <airlied@...ux.ie>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/8] drm/nouveau: Enable polling even if we have
 runtime PM

oooh, thanks for pointing that out. I should have grepped for this function
before doing that commit. There also appears to be another duplicate
drm_kms_helper_poll_enable() in nouveau_vga.c which also looks equally
suspecious as being useless. I will fix this up and also remove that other
duplicate call in the next version of this

On Thu, 2018-08-02 at 21:14 +0200, Lukas Wunner wrote:
> On Wed, Aug 01, 2018 at 05:14:52PM -0400, Lyude Paul wrote:
> > --- a/drivers/gpu/drm/nouveau/nouveau_drm.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
> > @@ -592,10 +592,11 @@ nouveau_drm_load(struct drm_device *dev, unsigned
> > long flags)
> >  		pm_runtime_allow(dev->dev);
> >  		pm_runtime_mark_last_busy(dev->dev);
> >  		pm_runtime_put(dev->dev);
> > -	} else {
> > -		/* enable polling for external displays */
> > -		drm_kms_helper_poll_enable(dev);
> >  	}
> > +
> > +	/* enable polling for connectors without hpd */
> > +	drm_kms_helper_poll_enable(dev);
> > +
> 
> I'm wondering why drm_kms_helper_poll_enable() is called here at all.
> Does the invocation in nouveau_display_init() not suffice?  Can there
> be a situation when nouveau_display_init() is not called despite there
> being connectors that need to be polled?
> 
> Thanks,
> 
> Lukas
-- 
Cheers,
	Lyude Paul