drm/i915: Get rid of the gm45 HPD live state nonsensedrm-intel-next-2023-03-07

The idea that ctg uses different HPD live state bits is
total nonsense, at least on my machine (Dell Latitude
E5400).

The only reason DP-B even works on my ctg is that DP-D
live state is stuck high, even though there is no physical
DP-D port. So when the detect checks DP-B live state it
sees the stuck live state of DP-D instead. If I hack
the driver to not register DP-D at all, and thus we never
enabe DP-D HPD, DP-B stops working as well.

Just to put some conclusive evidence into this mess,
here are the actual hotplug register values for each port:
 Everything disconnected:
                    PORT_HOTPLUG_EN (0x00061110): 0x00000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x00000000
                    PORT_HOTPLUG_EN (0x00061110): 0x08000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x08000000
                    PORT_HOTPLUG_EN (0x00061110): 0x10000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x00000000
                    PORT_HOTPLUG_EN (0x00061110): 0x20000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x00000000
 Only port B connected:
                    PORT_HOTPLUG_EN (0x00061110): 0x00000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x00000000
                    PORT_HOTPLUG_EN (0x00061110): 0x08000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x08000000
                    PORT_HOTPLUG_EN (0x00061110): 0x10000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x00000000
                    PORT_HOTPLUG_EN (0x00061110): 0x20000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x20000000
 Only port C connected:
                    PORT_HOTPLUG_EN (0x00061110): 0x00000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x00000000
                    PORT_HOTPLUG_EN (0x00061110): 0x08000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x08000000
                    PORT_HOTPLUG_EN (0x00061110): 0x10000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x10000000
                    PORT_HOTPLUG_EN (0x00061110): 0x20000000
                  PORT_HOTPLUG_STAT (0x00061114): 0x00000000

So the enable bit and live state bit always match 1:1.

Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230302161013.29213-4-ville.syrjala@linux.intel.com

2 files changed, 2 insertions, 39 deletions

diff --git a/drivers/gpu/drm/i915/display/g4x_dp.c b/drivers/gpu/drm/i915/display/g4x_dp.c
index a50ad0fff57c..920d570f7594 100644
--- a/drivers/gpu/drm/i915/display/g4x_dp.c
+++ b/drivers/gpu/drm/i915/display/g4x_dp.c
@@ -1197,29 +1197,6 @@ static bool g4x_digital_port_connected(struct intel_encoder *encoder)
 	return intel_de_read(dev_priv, PORT_HOTPLUG_STAT) & bit;
 }
 
-static bool gm45_digital_port_connected(struct intel_encoder *encoder)
-{
-	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
-	u32 bit;
-
-	switch (encoder->hpd_pin) {
-	case HPD_PORT_B:
-		bit = PORTB_HOTPLUG_LIVE_STATUS_GM45;
-		break;
-	case HPD_PORT_C:
-		bit = PORTC_HOTPLUG_LIVE_STATUS_GM45;
-		break;
-	case HPD_PORT_D:
-		bit = PORTD_HOTPLUG_LIVE_STATUS_GM45;
-		break;
-	default:
-		MISSING_CASE(encoder->hpd_pin);
-		return false;
-	}
-
-	return intel_de_read(dev_priv, PORT_HOTPLUG_STAT) & bit;
-}
-
 static bool ilk_digital_port_connected(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
@@ -1384,10 +1361,7 @@ bool g4x_dp_init(struct drm_i915_private *dev_priv,
 	dig_port->hpd_pulse = intel_dp_hpd_pulse;
 
 	if (HAS_GMCH(dev_priv)) {
-		if (IS_GM45(dev_priv))
-			dig_port->connected = gm45_digital_port_connected;
-		else
-			dig_port->connected = g4x_digital_port_connected;
+		dig_port->connected = g4x_digital_port_connected;
 	} else {
 		if (port == PORT_A)
 			dig_port->connected = ilk_digital_port_connected;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 9f4e4c3d6159..974cf8bdc056 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2379,18 +2379,7 @@
 #define CRT_HOTPLUG_DETECT_VOLTAGE_475MV	(1 << 2)
 
 #define PORT_HOTPLUG_STAT	_MMIO(DISPLAY_MMIO_BASE(dev_priv) + 0x61114)
-/*
- * HDMI/DP bits are g4x+
- *
- * WARNING: Bspec for hpd status bits on gen4 seems to be completely confused.
- * Please check the detailed lore in the commit message for for experimental
- * evidence.
- */
-/* Bspec says GM45 should match G4X/VLV/CHV, but reality disagrees */
-#define   PORTD_HOTPLUG_LIVE_STATUS_GM45	(1 << 29)
-#define   PORTC_HOTPLUG_LIVE_STATUS_GM45	(1 << 28)
-#define   PORTB_HOTPLUG_LIVE_STATUS_GM45	(1 << 27)
-/* G4X/VLV/CHV DP/HDMI bits again match Bspec */
+/* HDMI/DP bits are g4x+ */
 #define   PORTD_HOTPLUG_LIVE_STATUS_G4X		(1 << 27)
 #define   PORTC_HOTPLUG_LIVE_STATUS_G4X		(1 << 28)
 #define   PORTB_HOTPLUG_LIVE_STATUS_G4X		(1 << 29)