[Intel-gfx] [PATCH 5/6] drm/i915/glk: Don't attempt to sync DDI IO power well hw state

[Ander Conselvan de Oliveira]

Geminilake's DDI IO power wells can only be enabled after a DPLL is
running and must be disabled before disabling the DPLL. Attempting to
change its state outside of this conditions will result in timeouts.
That is the case when intel_power_domains_sync_hw() is called from
intel_power_domains_init_hw(), where the attempt to disable the DDI IO
for an enabled port will timeout, so don't attempt to sync the hw state
for those power wells.

Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira at intel.com>
---
 drivers/gpu/drm/i915/intel_runtime_pm.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index b729a39..4d2dc31 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -2220,6 +2220,25 @@ static struct i915_power_well bxt_power_wells[] = {
 	},
 };
 
+static void noop_power_well_sync_hw(struct drm_i915_private *dev_priv,
+				    struct i915_power_well *power_well)
+{
+}
+
+static const struct i915_power_well_ops glk_ddi_io_power_well_ops = {
+	/*
+	 * DDI IO power wells in GLK can only be enabled after a DPLL is
+	 * running and must be disabled before disabling the DPLL. Any
+	 * attempt to change its state in different condidtions will lead
+	 * to timeouts.
+	 */
+	.sync_hw = noop_power_well_sync_hw,
+
+	.enable = skl_power_well_enable,
+	.disable = skl_power_well_disable,
+	.is_enabled = skl_power_well_enabled,
+};
+
 static struct i915_power_well glk_power_wells[] = {
 	{
 		.name = "always-on",
@@ -2288,19 +2307,19 @@ static struct i915_power_well glk_power_wells[] = {
 	{
 		.name = "DDI A power well",
 		.domains = GLK_DISPLAY_DDI_A_POWER_DOMAINS,
-		.ops = &skl_power_well_ops,
+		.ops = &glk_ddi_io_power_well_ops,
 		.id = GLK_DISP_PW_DDI_A,
 	},
 	{
 		.name = "DDI B power well",
 		.domains = GLK_DISPLAY_DDI_B_POWER_DOMAINS,
-		.ops = &skl_power_well_ops,
+		.ops = &glk_ddi_io_power_well_ops,
 		.id = SKL_DISP_PW_DDI_B,
 	},
 	{
 		.name = "DDI C power well",
 		.domains = GLK_DISPLAY_DDI_C_POWER_DOMAINS,
-		.ops = &skl_power_well_ops,
+		.ops = &glk_ddi_io_power_well_ops,
 		.id = SKL_DISP_PW_DDI_C,
 	},
 };
-- 
2.9.3