i915: Fix i915 suspend delay

During system suspend, the "wait for ring buffer to empty" loop would
always time out after three seconds, because the faster cached ring
buffer head read would always return zero.  Force the slow-and-careful
PIO read on all but the first iterations of the loop to fix it.

This also removes the unused (and useless) 'actual_head' variable that
tried to approximate doing this, but did it incorrectly.

Cc: Chris Wilson <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Jesse Barnes <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: DRI mailing list <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions