open(/dev/dri/card0): No such file or directory — no radeon DRM device on this machine; trigger is hardware-gated.

--- arithmetic simulation (same guest) ---
nsamples default       : 16
pitch                  : 8 px
slice_tile_max (raw)   : 1
height                 : 8
LINEAR_GENERAL checks  : pitch_align=1 height_align=1 base_align=1 -> PASS; size check SKIPPED (linear hole)
value written to ib[track->cb_color_size_idx[0]] (= ib[0]): 0x00000000

ib[0] == 0 is a CP type-0 header, count=0, reg=0:
  GPU consumes ib[0]+ib[1] as one PACKET0 write and re-starts
  command execution at ib[2] — everything the validator saw as
  SET_ALU_CONST payload VALUES now executes as PACKETS.