On Mon, May 15, 2017 at 05:35:02PM +0800, Icenowy Zheng wrote: > > > 于 2017年5月15日 GMT+08:00 下午5:20:01, Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> 写到: > >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? > > Some engines (de2 mixer) doesn't use the ID. But 0 is a valid ID here. Surely it will at some point. > If we just store it in sunxi_engine, it should be assigned -1 for de2 mixer. > Is this applicable? > > If it's okay I will do so. Yes, it sounds reasonable. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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