SYNOPSIS

int drm_atomic_helper_check_modeset(struct drm_device * dev, struct drm_atomic_state * state);

ARGUMENTS

dev

DRM device

state

the driver state object

DESCRIPTION

Check the state object to see if the requested state is physically possible. This does all the crtc and connector related computations for an atomic update and adds any additional connectors needed for full modesets and calls down into ->mode_fixup functions of the driver backend.

crtc_state->mode_changed is set when the input mode is changed. crtc_state->connectors_changed is set when a connector is added or removed from the crtc. crtc_state->active_changed is set when crtc_state->active changes, which is used for dpms.

IMPORTANT

Drivers which update ->mode_changed (e.g. in their ->atomic_check hooks if a plane update can't be done without a full modeset) _must_ call this function afterwards after that change. It is permitted to call this function multiple times for the same update, e.g. when the ->atomic_check functions depend upon the adjusted dotclock for fifo space allocation and watermark computation.

RETURNS Zero for success or -errno

AUTHORS

Jesse Barnes <[email protected]>
Intel Corporation,         
        

Initial version

Laurent Pinchart <[email protected]>
Ideas on board SPRL,         
        

Driver internals

Daniel Vetter <[email protected]>
Intel Corporation,         
        

Contributions all over the place

Lukas Wunner <[email protected]>

vga_switcheroo documentation

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