[PATCH 4/4] drm/i915/dmc_wl: Allow enable_dmc_wl=3 to mean "always locked"

[Gustavo Sousa]

When debugging issues that might be related to the DMC wakelock code, it
might be useful to compare runs with the lock acquired while DC states
are enabled vs the regular case. If issues disappear with the former, it
might be a symptom of something wrong in our code. Support having this
"always locked" behavior with enable_dmc_wl=3.

Signed-off-by: Gustavo Sousa <gustavo.sousa at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_params.c | 2 +-
 drivers/gpu/drm/i915/display/intel_dmc_wl.c         | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c
index f0f388f38fa7..c4f1ab43fc0c 100644
--- a/drivers/gpu/drm/i915/display/intel_display_params.c
+++ b/drivers/gpu/drm/i915/display/intel_display_params.c
@@ -130,7 +130,7 @@ intel_display_param_named_unsafe(enable_psr2_sel_fetch, bool, 0400,
 
 intel_display_param_named_unsafe(enable_dmc_wl, int, 0400,
 	"Enable DMC wakelock "
-	"(-1=use per-chip default, 0=disabled, 1=enabled, 2=match any register) "
+	"(-1=use per-chip default, 0=disabled, 1=enabled, 2=match any register, 3=always locked) "
 	"Default: -1");
 
 __maybe_unused
diff --git a/drivers/gpu/drm/i915/display/intel_dmc_wl.c b/drivers/gpu/drm/i915/display/intel_dmc_wl.c
index 22e963da65c6..a277c5025f8d 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc_wl.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc_wl.c
@@ -57,6 +57,7 @@ enum {
 	ENABLE_DMC_WL_DISABLED,
 	ENABLE_DMC_WL_ENABLED,
 	ENABLE_DMC_WL_ANY_REGISTER,
+	ENABLE_DMC_WL_ALWAYS_LOCKED,
 	ENABLE_DMC_WL_MAX,
 };
 
@@ -312,6 +313,9 @@ static void intel_dmc_wl_sanitize_param(struct intel_display *display)
 	case ENABLE_DMC_WL_ANY_REGISTER:
 		desc = "match any register";
 		break;
+	case ENABLE_DMC_WL_ALWAYS_LOCKED:
+		desc = "always locked";
+		break;
 	default:
 		desc = "unknown";
 		break;
@@ -332,7 +336,8 @@ void intel_dmc_wl_init(struct intel_display *display)
 
 	INIT_DELAYED_WORK(&wl->work, intel_dmc_wl_work);
 	spin_lock_init(&wl->lock);
-	refcount_set(&wl->refcount, 0);
+	refcount_set(&wl->refcount,
+		     display->params.enable_dmc_wl == ENABLE_DMC_WL_ALWAYS_LOCKED ? 1 : 0);
 }
 
 /* Must only be called as part of enabling dynamic DC states. */
-- 
2.47.1