drm/i915: Enable pipe-a power well on chv

It seems that the pipe-a power well has replaced the disp2d power well
on chv. At least that's the case with the current punit firmware. So
enable the pipe-a power and expand its domains to cover everything the
disp2d well ought to cover.

The other power wells (apart from the cmnlane wells) still seem awol
in the current punit firmware. So leave them disabled in the code.

This fixes a hilarious oops during resume on bsw where
intel_hdmi_get_config() would read the port register and get back
0xffffffff and thus think the port is enabled on pipe D. It would then
go and index the pipe_to_crtc_mapping[] array with PIPE_D and blow up
when intel_hdmi_get_config() tries to write to crtc->config. Someone
really ought to replace all naked pipe_to_crtc_mapping[] uses with the
appropriate function call so we could add a warning there if the pipe
doesn't actually exist...

We must also call the power seqeuencer state reset function from
the pipe-a well disable just like we do from disp2d on vlv. Otherwise
the eDP panel won't recover at resume time since the PPS has lost its
hold on the port.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84903
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -587,6 +587,9 @@ static void chv_pipe_power_well_disable(struct drm_i915_private *dev_priv,
 		     power_well->data != PIPE_C);
 
 	chv_set_pipe_power_well(dev_priv, power_well, false);
+
+	if (power_well->data == PIPE_A)
+		vlv_power_sequencer_reset(dev_priv);
 }
 
 static void check_power_well_state(struct drm_i915_private *dev_priv,
@@ -938,12 +941,20 @@ static struct i915_power_well chv_power_wells[] = {
 		.data = PUNIT_POWER_WELL_DISP2D,
 		.ops = &vlv_display_power_well_ops,
 	},
+#endif
 	{
 		.name = "pipe-a",
-		.domains = CHV_PIPE_A_POWER_DOMAINS,
+		/*
+		 * FIXME: pipe A power well seems to be the new disp2d well.
+		 * At least all registers seem to be housed there. Figure
+		 * out if this a a temporary situation in pre-production
+		 * hardware or a permanent state of affairs.
+		 */
+		.domains = CHV_PIPE_A_POWER_DOMAINS | VLV_DISPLAY_POWER_DOMAINS,
 		.data = PIPE_A,
 		.ops = &chv_pipe_power_well_ops,
 	},
+#if 0
 	{
 		.name = "pipe-b",
 		.domains = CHV_PIPE_B_POWER_DOMAINS,