Re: [PATCH 3/8] drm: Add drm_for_each_connector_encoder_ids()

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Jun 27, 2018 at 06:07:39PM +0300, Ville Syrjälä wrote:
> On Wed, Jun 27, 2018 at 11:11:57AM +0200, Daniel Vetter wrote:
> > On Wed, Jun 27, 2018 at 11:08:48AM +0200, Daniel Vetter wrote:
> > > On Tue, Jun 26, 2018 at 08:47:09PM +0300, Ville Syrjala wrote:
> > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > 
> > > > Add a convenience macro for iterating connector->encoder_ids[].
> > > > Isolates the users from the implementation details.
> > > > 
> > > > Also use ARRAY_SIZE() when populating the array to avoid spreading
> > > > knowledge about the array size all over.
> > > > 
> > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > ---
> > > >  drivers/gpu/drm/drm_connector.c    | 22 ++++++++++------------
> > > >  drivers/gpu/drm/drm_fb_helper.c    |  6 +++---
> > > >  drivers/gpu/drm/drm_probe_helper.c |  9 +++++----
> > > >  include/drm/drm_connector.h        | 11 +++++++++++
> > > >  4 files changed, 29 insertions(+), 19 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> > > > index 2f9ebddd178e..c43646cb8145 100644
> > > > --- a/drivers/gpu/drm/drm_connector.c
> > > > +++ b/drivers/gpu/drm/drm_connector.c
> > > > @@ -321,7 +321,7 @@ int drm_mode_connector_attach_encoder(struct drm_connector *connector,
> > > >  	if (WARN_ON(connector->encoder))
> > > >  		return -EINVAL;
> > > >  
> > > > -	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> > > > +	for (i = 0; i < ARRAY_SIZE(connector->encoder_ids); i++) {
> > > >  		if (connector->encoder_ids[i] == 0) {
> > > >  			connector->encoder_ids[i] = encoder->base.id;
> > > >  			return 0;
> > > > @@ -1693,6 +1693,7 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
> > > >  	int encoders_count = 0;
> > > >  	int ret = 0;
> > > >  	int copied = 0;
> > > > +	u32 encoder_id;
> > > >  	int i;
> > > >  	struct drm_mode_modeinfo u_mode;
> > > >  	struct drm_mode_modeinfo __user *mode_ptr;
> > > > @@ -1708,22 +1709,19 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
> > > >  	if (!connector)
> > > >  		return -ENOENT;
> > > >  
> > > > -	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
> > > > -		if (connector->encoder_ids[i] != 0)
> > > > -			encoders_count++;
> > > > +	drm_for_each_connector_encoder_ids(connector, encoder_id, i)
> > > > +		encoders_count++;
> > > >  
> > > >  	if ((out_resp->count_encoders >= encoders_count) && encoders_count) {
> > > >  		copied = 0;
> > > >  		encoder_ptr = (uint32_t __user *)(unsigned long)(out_resp->encoders_ptr);
> > > > -		for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> > > > -			if (connector->encoder_ids[i] != 0) {
> > > > -				if (put_user(connector->encoder_ids[i],
> > > > -					     encoder_ptr + copied)) {
> > > > -					ret = -EFAULT;
> > > > -					goto out;
> > > > -				}
> > > > -				copied++;
> > > > +
> > > > +		drm_for_each_connector_encoder_ids(connector, encoder_id, i) {
> > > > +			if (put_user(encoder_id, encoder_ptr + copied)) {
> > > > +				ret = -EFAULT;
> > > > +				goto out;
> > > >  			}
> > > > +			copied++;
> > > >  		}
> > > >  	}
> > > >  	out_resp->count_encoders = encoders_count;
> > > > diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> > > > index 61c39cd75a27..e086b08748f4 100644
> > > > --- a/drivers/gpu/drm/drm_fb_helper.c
> > > > +++ b/drivers/gpu/drm/drm_fb_helper.c
> > > > @@ -2326,12 +2326,12 @@ static bool drm_target_preferred(struct drm_fb_helper *fb_helper,
> > > >  static bool connector_crtc_ok(struct drm_connector *connector,
> > > >  			      struct drm_crtc *crtc)
> > > >  {
> > > > +	u32 encoder_id;
> > > >  	int i;
> > > >  
> > > > -	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> > > > +	drm_for_each_connector_encoder_ids(connector, encoder_id, i) {
> > > >  		struct drm_encoder *encoder =
> > > > -			drm_encoder_find(connector->dev, NULL,
> > > > -					 connector->encoder_ids[i]);
> > > > +			drm_encoder_find(connector->dev, NULL, encoder_id);
> > > >  
> > > >  		if (encoder->possible_crtcs & drm_crtc_mask(crtc))
> > > >  			return true;
> > > > diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> > > > index 527743394150..0239f76c52fb 100644
> > > > --- a/drivers/gpu/drm/drm_probe_helper.c
> > > > +++ b/drivers/gpu/drm/drm_probe_helper.c
> > > > @@ -88,9 +88,9 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode,
> > > >  			    struct drm_connector *connector)
> > > >  {
> > > >  	struct drm_device *dev = connector->dev;
> > > > -	uint32_t *ids = connector->encoder_ids;
> > > >  	enum drm_mode_status ret = MODE_OK;
> > > > -	unsigned int i;
> > > > +	u32 encoder_id;
> > > > +	int i;
> > > >  
> > > >  	/* Step 1: Validate against connector */
> > > >  	ret = drm_connector_mode_valid(connector, mode);
> > > > @@ -98,8 +98,9 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode,
> > > >  		return ret;
> > > >  
> > > >  	/* Step 2: Validate against encoders and crtcs */
> > > > -	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> > > > -		struct drm_encoder *encoder = drm_encoder_find(dev, NULL, ids[i]);
> > > > +	drm_for_each_connector_encoder_ids(connector, encoder_id, i) {
> > > > +		struct drm_encoder *encoder =
> > > > +			drm_encoder_find(dev, NULL, encoder_id);
> > > >  		struct drm_crtc *crtc;
> > > >  
> > > >  		if (!encoder)
> > > > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> > > > index 14ab58ade87f..4a0363f7dd8c 100644
> > > > --- a/include/drm/drm_connector.h
> > > > +++ b/include/drm/drm_connector.h
> > > > @@ -1193,4 +1193,15 @@ void drm_connector_list_iter_end(struct drm_connector_list_iter *iter);
> > > >  #define drm_for_each_connector_iter(connector, iter) \
> > > >  	while ((connector = drm_connector_list_iter_next(iter)))
> > > >  
> > > > +/**
> > > > + * drm_for_each_connector_encoder_ids - iterate connector encoder_ids[]
> > > 
> > > &drm_connector.encoder_ids would give you a (fairly direct) link. Just a
> > > nitpick.
> > > 
> > > Wrt the api: I think including the drm_encoder_find would be useful here -
> > > it's what 2/3 users want anyway, and the ioctl can easily look up the id
> > > again by following encoder->base.id. And then maybe call the function a
> > > bit differently, I think usually we go with
> > > $parent_object_for_each_$iterated_thing, so
> > > drm_connector_for_each_encoder(). There's also the
> > > for_each_$thing_in_$parent_object pattern (used for atomic states), but I
> > > think that's less fitting here.
> > > 
> > > Apologies for the interface bikeshedding ...
> > 
> > Looking at all the patches it's 15 places that want the drm_encoder_find
> > integrated vs. 4 that don't want it (without further refactoring). So even
> > more reasons for drm_connector_for_each_encoder imo.
> 
> I had that same thought initially, but then forgot about it for
> some reason. It does indeed lead to an even neater result.
> 
> Although it should be somewhat obvious that there can only be one
> currently used encoder for a connector, I think we may want to name
> this eg. drm_connector_for_each_possible_encoder() to make it super
> clear what we're talking about.

Yeah, that sounds like an even better name.
-Daniel

> 
> > -Daniel
> > 
> > > -Daniel
> > > 
> > > > + * @connector: &struct drm_connector pointer used as cursor
> > > > + * @encoder_id: the encoder ID
> > > > + * @__i: int iteration cursor, for macro-internal use
> > > > + */
> > > > +#define drm_for_each_connector_encoder_ids(connector, encoder_id, __i) \
> > > > +	for ((__i) = 0; (__i) < ARRAY_SIZE((connector)->encoder_ids) && \
> > > > +		     (connector)->encoder_ids[(__i)] != 0; (__i)++) \
> > > > +		for_each_if((encoder_id) = (connector)->encoder_ids[(__i)])
> > > > +
> > > >  #endif
> > > > -- 
> > > > 2.16.4
> > > > 
> > > > _______________________________________________
> > > > dri-devel mailing list
> > > > dri-devel@lists.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > > 
> > > -- 
> > > Daniel Vetter
> > > Software Engineer, Intel Corporation
> > > http://blog.ffwll.ch
> > 
> > -- 
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
> 
> -- 
> Ville Syrjälä
> Intel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel