[Intel-gfx] [RFC 1/4] drm/i915/quirks: Add quirk for 480MHz CDCLK step

[Chaitanya Kumar Borah]

A new CDCLK step of 480MHz has been added on SKUs that has a
RPL-U device id. This is done to support 120Hz displays with
more efficiency.

RPL-U device ids are currently added within the RPL-P sub
platform. It seems to be an overkill to add a separate sub
platform just to support this change. Therefore, quirks
are a good way to achieve the same.

BSpec: 55409

Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
---
 drivers/gpu/drm/i915/display/intel_quirks.c | 14 ++++++++++++++
 drivers/gpu/drm/i915/display/intel_quirks.h |  1 +
 2 files changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_quirks.c b/drivers/gpu/drm/i915/display/intel_quirks.c
index 6e48d3bcdfec..0a30499835b3 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.c
+++ b/drivers/gpu/drm/i915/display/intel_quirks.c
@@ -65,6 +65,16 @@ static void quirk_no_pps_backlight_power_hook(struct drm_i915_private *i915)
 	drm_info(&i915->drm, "Applying no pps backlight power quirk\n");
 }
 
+/*
+ * A new step of 480MHz has been added on SKUs that have a RPL-U device id.
+ * This particular step is to better support 120Hz panels.
+ */
+static void quirk_480mhz_cdclk_step_hook(struct drm_i915_private *i915)
+{
+	intel_set_quirk(i915, QUIRK_480MHZ_CDCLK_STEP);
+	drm_info(&i915->drm, "Applying 480MHz CDCLK step quirk\n");
+}
+
 struct intel_quirk {
 	int device;
 	int subsystem_vendor;
@@ -199,6 +209,10 @@ static struct intel_quirk intel_quirks[] = {
 	/* ECS Liva Q2 */
 	{ 0x3185, 0x1019, 0xa94d, quirk_increase_ddi_disabled_time },
 	{ 0x3184, 0x1019, 0xa94d, quirk_increase_ddi_disabled_time },
+	/* RPL-U */
+	{ 0xA7A1, PCI_ANY_ID, PCI_ANY_ID, quirk_480mhz_cdclk_step_hook },
+	{ 0xA721, PCI_ANY_ID, PCI_ANY_ID, quirk_480mhz_cdclk_step_hook },
+	{ 0xA7A9, PCI_ANY_ID, PCI_ANY_ID, quirk_480mhz_cdclk_step_hook },
 };
 
 void intel_init_quirks(struct drm_i915_private *i915)
diff --git a/drivers/gpu/drm/i915/display/intel_quirks.h b/drivers/gpu/drm/i915/display/intel_quirks.h
index 10a4d163149f..71e05684f5f4 100644
--- a/drivers/gpu/drm/i915/display/intel_quirks.h
+++ b/drivers/gpu/drm/i915/display/intel_quirks.h
@@ -17,6 +17,7 @@ enum intel_quirk_id {
 	QUIRK_INVERT_BRIGHTNESS,
 	QUIRK_LVDS_SSC_DISABLE,
 	QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK,
+	QUIRK_480MHZ_CDCLK_STEP,
 };
 
 void intel_init_quirks(struct drm_i915_private *i915);
-- 
2.25.1