NV50_DISP_WNDW_SEM0
#define NV50_DISP_BASE_SEM0(c) NV50_DISP_WNDW_SEM0(0 + (c))
#define NV50_DISP_OVLY_SEM0(c) NV50_DISP_WNDW_SEM0(4 + (c))
wndw->sema = NV50_DISP_WNDW_SEM0(wndw->id);