Re: [PATCH] drm/sysfs: Send out uevent when connector->force changes

From: Daniel Vetter <daniel@ffwll.ch>
To: Chris Wilson <chris@chris-wilson.co.uk>,
	Daniel Vetter <daniel@ffwll.ch>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
	Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH] drm/sysfs: Send out uevent when connector->force changes
Date: Tue, 24 Nov 2015 11:51:09 +0100	[thread overview]
Message-ID: <20151124105109.GL17050@phenom.ffwll.local> (raw)
In-Reply-To: <20151120092514.GG24442@nuc-i3427.alporthouse.com>

On Fri, Nov 20, 2015 at 09:25:14AM +0000, Chris Wilson wrote:
> On Fri, Nov 20, 2015 at 09:11:00AM +0100, Daniel Vetter wrote:
> > On Thu, Nov 19, 2015 at 09:06:04PM +0000, Chris Wilson wrote:
> > > On Thu, Nov 19, 2015 at 05:46:50PM +0100, Daniel Vetter wrote:
> > > > To avoid even more code duplication punt this all to the probe worker,
> > > > which needs some slight adjustment to also generate a uevent when the
> > > > status has changed to due connector->force.
> > > > 
> > > > v2: Instead of running the output_poll_work (which is kinda the wrong
> > > > thing and a layering violation since it's an internal of the probe
> > > > helpers), or calling ->detect (which is again a layering violation
> > > > since it's used only by probe helpers) just call the official
> > > > ->fill_modes function, like a GET_CONNECTOR ioctl call.
> > > > 
> > > > v3: Restore the accidentally removed forced-probe for echo "detect" >
> > > > force.
> > > > 
> > > 
> > > > diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> > > > index 9ac4ffa6cce3..df66d9447cb0 100644
> > > > --- a/drivers/gpu/drm/drm_sysfs.c
> > > > +++ b/drivers/gpu/drm/drm_sysfs.c
> > > > @@ -167,47 +167,35 @@ static ssize_t status_store(struct device *device,
> > > >  {
> > > >  	struct drm_connector *connector = to_drm_connector(device);
> > > >  	struct drm_device *dev = connector->dev;
> > > > -	enum drm_connector_status old_status;
> > > > +	enum drm_connector_force old_force;
> > > >  	int ret;
> > > >  
> > > >  	ret = mutex_lock_interruptible(&dev->mode_config.mutex);
> > > >  	if (ret)
> > > >  		return ret;
> > > >  
> > > > -	old_status = connector->status;
> > > > +	old_force = connector->force;
> > > >  
> > > > -	if (sysfs_streq(buf, "detect")) {
> > > > +	if (sysfs_streq(buf, "detect"))
> > > >  		connector->force = 0;
> > > > -		connector->status = connector->funcs->detect(connector, true);
> > > > -	} else if (sysfs_streq(buf, "on")) {
> > > > +	else if (sysfs_streq(buf, "on"))
> > > >  		connector->force = DRM_FORCE_ON;
> > > > -	} else if (sysfs_streq(buf, "on-digital")) {
> > > > +	else if (sysfs_streq(buf, "on-digital"))
> > > >  		connector->force = DRM_FORCE_ON_DIGITAL;
> > > > -	} else if (sysfs_streq(buf, "off")) {
> > > > +	else if (sysfs_streq(buf, "off"))
> > > >  		connector->force = DRM_FORCE_OFF;
> > > > -	} else
> > > > +	else
> > > >  		ret = -EINVAL;
> > > >  
> > > > -	if (ret == 0 && connector->force) {
> > > > -		if (connector->force == DRM_FORCE_ON ||
> > > > -		    connector->force == DRM_FORCE_ON_DIGITAL)
> > > > -			connector->status = connector_status_connected;
> > > > -		else
> > > > -			connector->status = connector_status_disconnected;
> > > > -		if (connector->funcs->force)
> > > > -			connector->funcs->force(connector);
> > > > -	}
> > > > -
> > > > -	if (old_status != connector->status) {
> > > > -		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
> > > > +	if (old_force != connector->force || !connector->force) {
> > > > +		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] force updated from %d to %d or reprobing\n",
> > > >  			      connector->base.id,
> > > >  			      connector->name,
> > > > -			      old_status, connector->status);
> > > > +			      old_force, connector->force);
> > > >  
> > > > -		dev->mode_config.delayed_event = true;
> > > > -		if (dev->mode_config.poll_enabled)
> > > > -			schedule_delayed_work(&dev->mode_config.output_poll_work,
> > > > -					      0);
> > > > +		connector->funcs->fill_modes(connector,
> > > > +					     dev->mode_config.max_width,
> > > > +					     dev->mode_config.max_height);
> > > 
> > > This now does fill_modes() before we call detect(). We rely on the
> > > ordering of detect() before doing fill_modes() as in many cases we use
> > > the EDID gathered in detect() to generate the modes (if I am not
> > > mistaken, I think we merged those patches to cache the EDID for a
> > > detection cycle).
> > 
> > ->fill_modes = drm_helper_probe_single_connector_modes which then calls
> > ->detect. By going this way we avoid duplicating the "send uevent if
> > anything changed" logic all over the place, and ->detect becomes purely a
> > helper internal callback to get at the mode list for hotpluggeable
> > outputs.
> 
> Ok, that struck me as a little surprising - I was thinking of lower level
> get_modes apparently.
> 
> With that resolved,
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

Applied to drm-misc, thanks for the review.

> > Yes this means that ->detect should become a helper function, but that's
> > quite an invasive change.
> 
> And something like .fill_modes -> .probe (after removing .detect).

Hm, not sure. For panels we never really probe anything, the important bit
is (at least for the caller in drm_crtc.c) that it fills in the
connectore->modes list. Given that I think the current name is okish.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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