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Submitted by Daniel Stone @daniels

Assigned to Daniel Stone @daniels

Link to original bug (#7634)

Description

Currently in compositor-drm, we have something like the below pseudocode:

struct drm_fb *drm_fb_get_from_bo(struct gbm_bo *bo, uint32_t format)  
{  
        struct drm_fb *fb = gbm_bo_get_user_data(bo);  
        if (fb)  
                return fb;  

        drmModeAddFB2(..., format, &fb->fb_id);  
}  

drm_output_prepare_{scanout,overlay}_view()  
{  
        uint32_t format;  
        struct drm_fb *fb;  

        format = gbm_bo_get_format(bo);  
        if (surface_is_opaque())  
                format = get_opaque_format(format);  
        fb = drm_fb_get_from_bo(bo);  
}  

This assumes that the lifetime of a gbm_bo is usefully tied to the lifetime of the surface_is_opaque() determination of a surface, where we check to see if the opaque area covers the whole area of the view.

This already breaks today in contrived multi-view situations, and could also break if the gbm_bo ends up living longer than a single repaint cycle in future.

I don't have a great idea of how to fix this right now, apart from maybe creating multiple FBs on demand.