Re: [PATCH v7 06/12] drm/bridge: Add the necessary bits to support bus format negotiation

[Boris Brezillon <boris.brezillon@collabora.com>]

On Wed, 22 Jan 2020 23:44:28 +0000 (UTC)
Jonas Karlman <jonas@kwiboo.se> wrote:

> > +static int
> > +drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
> > +					struct drm_crtc_state *crtc_state,
> > +					struct drm_connector_state *conn_state)
> > +{
> > +	struct drm_connector *conn = conn_state->connector;
> > +	struct drm_encoder *encoder = bridge->encoder;
> > +	struct drm_bridge_state *last_bridge_state;
> > +	unsigned int i, num_out_bus_fmts;
> > +	struct drm_bridge *last_bridge;
> > +	u32 *out_bus_fmts;
> > +	int ret = 0;
> > +
> > +	last_bridge = list_last_entry(&encoder->bridge_chain,
> > +				      struct drm_bridge, chain_node);
> > +	last_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
> > +							    last_bridge);
> > +
> > +	if (last_bridge->funcs->atomic_get_output_bus_fmts) {
> > +		const struct drm_bridge_funcs *funcs = last_bridge->funcs;
> > +
> > +		/*
> > +		 * If the driver implements ->atomic_get_output_bus_fmts() it
> > +		 * should also implement the atomic state hooks.
> > +		 */
> > +		if (WARN_ON(last_bridge_state))  
> 
> This looks wrong, with this changed to WARN_ON(!last_bridge_state)
> my RK3328 HDMI2.0/YUV444/YUV420/10-bit branch at [1] starts working.
> 
> With WARN_ON(last_bridge_state) I get:
> 
> [    6.606658] WARNING: CPU: 0 PID: 167 at drivers/gpu/drm/drm_bridge.c:746 drm_atomic_bridge_chain_check+0x2b8/0x308
> [    6.606673] Hardware name: Pine64 Rock64 (DT)
> 
> [    6.606754] Call trace:
> [    6.606759]  drm_atomic_bridge_chain_check+0x2b8/0x308
> [    6.606764]  drm_atomic_helper_check_modeset+0x89c/0xab8
> [    6.606768]  drm_atomic_helper_check+0x1c/0xa0
> [    6.606772]  drm_atomic_check_only+0x464/0x708
> [    6.606777]  drm_atomic_commit+0x18/0x58

Add

const drm_bridge_funcs ... = {
	...
	.atomic_reset = drm_atomic_helper_bridge_reset,
	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
	...
};

and that should work.

> 
> [1] https://github.com/Kwiboo/linux-rockchip/commits/next-20200122-bus-format
> 
> Regards,
> Jonas