drm/i915: Make turning on/off PW1 and Misc I/O part of the init/fini sequences

Before this patch, we used the intel_display_power_{get,put} functions
to make sure the PW1 and Misc I/O power wells were enabled all the
time while LCPLL was enabled. We called a get() at
intel_ddi_pll_init() when we discovered that LCPLL was enabled, then
we would call put/get at skl_{un,}init_cdclk().

The problem is that skl_uninit_cdclk() is indirectly called by
intel_runtime_suspend(). So it will only release its power well
_after_ we already decided to runtime suspend. But since we only
decide to runtime suspend after all power wells and refcounts are
released, that basically means we will never decide to runtime
suspend.

So what this patch does to fix that problem is move the PW1 + Misc I/O
power well handling out of the runtime PM mechanism: instead of
calling intel_display_power_{get_put} - functions that touch the
refcount -, we'll call the low level intel_power_well_{en,dis}able,
which don't change the refcount. This way, it is now possible for the
refcount to actually reach zero, and we'll now start runtime
suspending/resuming.

v2 (from Paulo):
  - Write a commit message since the original patch left it empty.
  - Rebase after the intel_power_well_{en,dis}able rename.
  - Use lookup_power_well() instead of hardcoded indexes.

Testcase: igt/pm_rpm/rte (and every other rpm test)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92211
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92605
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446657859-9598-4-git-send-email-imre.deak@intel.com

1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 8b4ec4b27ce4..8546f2c5eee8 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -1782,6 +1782,34 @@ static struct i915_power_well skl_power_wells[] = {
 	},
 };
 
+void skl_pw1_misc_io_init(struct drm_i915_private *dev_priv)
+{
+	struct i915_power_well *well;
+
+	if (!IS_SKYLAKE(dev_priv))
+		return;
+
+	well = lookup_power_well(dev_priv, SKL_DISP_PW_1);
+	intel_power_well_enable(dev_priv, well);
+
+	well = lookup_power_well(dev_priv, SKL_DISP_PW_MISC_IO);
+	intel_power_well_enable(dev_priv, well);
+}
+
+void skl_pw1_misc_io_fini(struct drm_i915_private *dev_priv)
+{
+	struct i915_power_well *well;
+
+	if (!IS_SKYLAKE(dev_priv))
+		return;
+
+	well = lookup_power_well(dev_priv, SKL_DISP_PW_1);
+	intel_power_well_disable(dev_priv, well);
+
+	well = lookup_power_well(dev_priv, SKL_DISP_PW_MISC_IO);
+	intel_power_well_disable(dev_priv, well);
+}
+
 static struct i915_power_well bxt_power_wells[] = {
 	{
 		.name = "always-on",