[PATCH] Revert "drm/i915: Propagate errors on awaiting already signaled fences"

[Chris Wilson]

Quoting Jason Ekstrand (2021-03-05 17:05:46)
> This reverts commit 9e31c1fe45d555a948ff66f1f0e3fe1f83ca63f7.  Ever
> since that commit, we've been having issues where a hang in one client
> can propagate to another.  In particular, a hang in an app can propagate
> to the X server which causes the whole desktop to lock up.

The fence error handling is required to prevent user's circumventing
incomplete work, such as security validation or escaping isolation.
-Chris