1344 /** * How many users have pinned this object in GTT space. The following * users can each hold at most one reference: pwrite/pread, pin_ioctl * (via user_pin_count), execbuffer (objects are not allowed multiple * times for the same batchbuffer), and the framebuffer code. When * switching/pageflipping, the framebuffer code has at most two buffers * pinned per crtc. * * In the worst case this is 1 + 1 + 1 + 2*2 = 7. That would fit into 3 * bits with absolutely no headroom. So use 4 bits. */