alistair23-linux/drivers/gpu
Paulo Zanoni 5ade2c2f58 drm/i915: wait for IPS_ENABLE when enabling IPS
At the end of haswell_crtc_enable we have an intel_wait_for_vblank
with a big comment, and the message suggests it's a workaround for
something we don't really understand. So I removed that wait and
started getting HW state readout error messages saying that the IPS
state is not what we expected.

I investigated and concluded that after you write IPS_ENABLE to
IPS_CTL, the bit will only actually become 1 on the next vblank. So
add code to wait for the IPS_ENABLE bit. We don't really need this
wait right now due to the wait I already mentioned, but at least this
one has a reason to be there, while the other one is just to
workaround some problem: we may remove it in the future.

The wait also acts as a POSTING_READ which we missed.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-10-10 12:47:11 +02:00
..
drm drm/i915: wait for IPS_ENABLE when enabling IPS 2013-10-10 12:47:11 +02:00
host1x drm: Make irq_enabled bool 2013-10-09 15:55:32 +10:00
vga vgaarb: Fix VGA decodes changes 2013-09-03 19:17:59 +02:00
Makefile