Some, but not all, callers of obj->vmap() would check if return
IS_ERR(). So let's actually return an error if vmap() fails. And fixup
the call-sites that were not handling this properly.
Signed-off-by: Rob Clark <robdclark@gmail.com>
To ease debugging, add debugfs file which can be cat/tail'd to log
submits, along with fence #. If GPU hangs, you can look at 'gpu'
debugfs file to find last completed fence and current register state,
and compare with logged rd file to narrow down the DRAW_INDX which
triggered the GPU hang.
Signed-off-by: Rob Clark <robdclark@gmail.com>