On Mon, May 15, 2017 at 12:30:37AM +0800, Icenowy Zheng wrote: > As we are going to add support for the Allwinner DE2 engine in sun4i-drm > driver, we will finally have two types of display engines -- the DE1 > backend and the DE2 mixer. They both do some display blending and feed > graphics data to TCON, and is part of the "Display Engine" called by > Allwinner, so I choose to call them both "engine" here. > > Abstract the engine type to a new struct with an ops struct, which contains > functions that should be called outside the engine-specified code (in > TCON, CRTC or TV Encoder code). > > Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx> > Reviewed-by: Chen-Yu Tsai <wens@xxxxxxxx> > --- > Changes in v7: > - Mention "Display Engine" for the name "engine". > - Fixed some small issues found by Chen-Yu and added his ACK. > Changes in v6: > - Rebased on wens's multi-pipeline patchset. > - Split out Makefile changes. You also added a get_id callback here... > +static const struct sunxi_engine_ops sun4i_backend_engine_ops = { > + .commit = sun4i_backend_commit, > + .layers_init = sun4i_layers_init, > + .apply_color_correction = sun4i_backend_apply_color_correction, > + .disable_color_correction = sun4i_backend_disable_color_correction, > +}; > + ... that you don't populate ... > @@ -477,7 +481,7 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master, > dev_set_drvdata(dev, tcon); > tcon->drm = drm; > tcon->dev = dev; > - tcon->id = backend->id; > + tcon->id = sunxi_engine_get_id(engine); ... that you call to fill the TCON ID ... > +/** > + * sunxi_engine_get_id - Get the ID of the engine. > + * @engine: pointer to the engine > + * > + * If the ID is not necessary, just do not implement it in sunxi_engine_ops, > + * and a default -1 will be returned. > + */ > +static inline int > +sunxi_engine_get_id(struct sunxi_engine *engine) > +{ > + if (engine->ops && engine->ops->get_id) > + return engine->ops->get_id(engine); > + > + return -1; ... and will return -1 if not populated, which essentially means that instead of having 0 or 1, we're now having -1 as our id. This is a regression, and I'm even wondering if we can't just store the ID in the sunxi_engine structure. Is anything preventing us to do that, instead of using a callback? Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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