[Intel-gfx] [PATCH v3 03/22] drm/i915: Get rid of the gm45 HPD live state nonsense

[Jani Nikula]

On Wed, 22 Feb 2023, Ville Syrjala <ville.syrjala at linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> 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.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

I'll take your word for it.

Acked-by: Jani Nikula <jani.nikula at intel.com>


> ---
>  drivers/gpu/drm/i915/display/g4x_dp.c | 28 +--------------------------
>  drivers/gpu/drm/i915/i915_reg.h       | 13 +------------
>  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
> @@ -1196,31 +1196,8 @@ 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);
>  	u32 bit = dev_priv->display.hotplug.hpd[encoder->hpd_pin];
> @@ -1383,12 +1360,9 @@ 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;
>  		else
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c1efa655fb68..de58695ad1c0 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2482,20 +2482,9 @@
>  #define CRT_HOTPLUG_DETECT_VOLTAGE_325MV	(0 << 2)
>  #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)
>  #define   PORTD_HOTPLUG_INT_STATUS		(3 << 21)

-- 
Jani Nikula, Intel Open Source Graphics Center