Re: [PATCH v4] drm/i915/glk: Add Quirk for GLK NUC HDMI port issues.

[Imre Deak <imre.deak@intel.com>]

On Tue, Jul 03, 2018 at 01:16:40PM -0700, clinton.a.taylor@intel.com wrote:
> From: Clint Taylor <clinton.a.taylor@intel.com>
> 
> On GLK NUC platforms the HDMI retiming buffer needs additional disabled
> time to correctly sync to a faster incoming signal.
> 
> When measured on a scope the highspeed lines of the HDMI clock turn off
>  for ~400uS during a normal resolution change. The HDMI retimer on the
>  GLK NUC appears to require at least a full frame of quiet time before a
> new faster clock can be correctly sync'd. Wait 100ms due to msleep
> inaccuracies while waiting for a completed frame. Add a quirk to the
> driver for GLK boards that use ITE66317 HDMI retimers.
> 
> V2: Add more devices to the quirk list
> V3: Delay increased to 100ms, check to confirm crtc type is HDMI.
> V4: crtc type check extended to include _DDI and whitespace fixes
> 
> Cc: Imre Deak <imre.deak@intel.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105887
> Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h      |  1 +
>  drivers/gpu/drm/i915/intel_ddi.c     | 18 +++++++++++++++---
>  drivers/gpu/drm/i915/intel_display.c | 20 +++++++++++++++++++-
>  drivers/gpu/drm/i915/intel_drv.h     |  3 +--
>  4 files changed, 36 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 2cefe4c..c1526ea 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -650,6 +650,7 @@ enum intel_sbi_destination {
>  #define QUIRK_BACKLIGHT_PRESENT (1<<3)
>  #define QUIRK_PIN_SWIZZLED_PAGES (1<<5)
>  #define QUIRK_INCREASE_T12_DELAY (1<<6)
> +#define QUIRK_INCREASE_DDI_DISABLED_TIME (1<<7)
>  
>  struct intel_fbdev;
>  struct intel_fbc_work;
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 0319825..6d33010 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1807,15 +1807,27 @@ void intel_ddi_enable_transcoder_func(const struct intel_crtc_state *crtc_state)
>  	I915_WRITE(TRANS_DDI_FUNC_CTL(cpu_transcoder), temp);
>  }
>  
> -void intel_ddi_disable_transcoder_func(struct drm_i915_private *dev_priv,
> -				       enum transcoder cpu_transcoder)
> +/* Quirk time at 100ms for reliable operation */
> +#define DDI_DISABLED_QUIRK_TIME 100

No need for this define as I commented earlier.

> +
> +void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state)
>  {
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
> +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +
>  	i915_reg_t reg = TRANS_DDI_FUNC_CTL(cpu_transcoder);
>  	uint32_t val = I915_READ(reg);
> -

Removed w/s from the wrong spot.

>  	val &= ~(TRANS_DDI_FUNC_ENABLE | TRANS_DDI_PORT_MASK | TRANS_DDI_DP_VC_PAYLOAD_ALLOC);
>  	val |= TRANS_DDI_PORT_NONE;
>  	I915_WRITE(reg, val);
> +
> +	if (dev_priv->quirks & QUIRK_INCREASE_DDI_DISABLED_TIME &&
> +	    (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI) ||
> +	     intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DDI))) {

Hm, INTEL_OUTPUT_DDI is not a possible output type, the whole encoder
enable/disable sequence would be broken with that. Even during module
loading/HW readout we should already set the proper HDMI/DP type in
intel_modeset_pipe_config().

Looking now at the bug report [1], the reporter is using an old kernel,
where we left encoder->type at INTEL_OUTPUT_UNKNOWN during HW readout
and set it correctly only after the first modeset. That could be
addressed by adding INTEL_OUTPUT_UNKNOWN when backporting the workaround,
but in this patch we should only check for INTEL_OUTPUT_HDMI.

> +		DRM_DEBUG_KMS("Quirk Increase DDI disabled time\n");
> +		msleep(DDI_DISABLED_QUIRK_TIME);

Just msleep(100); as I commented earlier.

[1] https://bugs.freedesktop.org/show_bug.cgi?id=105887#c110

> +	}
>  }
>  
>  int intel_ddi_toggle_hdcp_signalling(struct intel_encoder *intel_encoder,
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 681e071..8d31ff3 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -5837,7 +5837,7 @@ static void haswell_crtc_disable(struct intel_crtc_state *old_crtc_state,
>  		intel_ddi_set_vc_payload_alloc(old_crtc_state, false);
>  
>  	if (!transcoder_is_dsi(cpu_transcoder))
> -		intel_ddi_disable_transcoder_func(dev_priv, cpu_transcoder);
> +		intel_ddi_disable_transcoder_func(old_crtc_state);
>  
>  	if (INTEL_GEN(dev_priv) >= 9)
>  		skylake_scaler_disable(intel_crtc);
> @@ -14847,6 +14847,17 @@ static void quirk_increase_t12_delay(struct drm_device *dev)
>  	DRM_INFO("Applying T12 delay quirk\n");
>  }
>  
> +/* GeminiLake NUC HDMI outputs require additional off time
> + * this allows the onboard retimer to correctly sync to signal
> + */
> +static void quirk_increase_ddi_disabled_time(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +
> +	dev_priv->quirks |= QUIRK_INCREASE_DDI_DISABLED_TIME;
> +	DRM_INFO("Applying Increase DDI Disabled quirk\n");
> +}
> +
>  struct intel_quirk {
>  	int device;
>  	int subsystem_vendor;
> @@ -14933,6 +14944,13 @@ static int intel_dmi_reverse_brightness(const struct dmi_system_id *id)
>  
>  	/* Toshiba Satellite P50-C-18C */
>  	{ 0x191B, 0x1179, 0xF840, quirk_increase_t12_delay },
> +
> +	/* GeminiLake NUC */
> +	{ 0x3185, 0x8086, 0x2072, quirk_increase_ddi_disabled_time },
> +	{ 0x3184, 0x8086, 0x2072, quirk_increase_ddi_disabled_time },
> +	/* ASRock ITX*/
> +	{ 0x3185, 0x1849, 0x2212, quirk_increase_ddi_disabled_time },
> +	{ 0x3184, 0x1849, 0x2212, quirk_increase_ddi_disabled_time },
>  };
>  
>  static void intel_init_quirks(struct drm_device *dev)
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index b9b7032..2490221 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1384,8 +1384,7 @@ void hsw_fdi_link_train(struct intel_crtc *crtc,
>  void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port);
>  bool intel_ddi_get_hw_state(struct intel_encoder *encoder, enum pipe *pipe);
>  void intel_ddi_enable_transcoder_func(const struct intel_crtc_state *crtc_state);
> -void intel_ddi_disable_transcoder_func(struct drm_i915_private *dev_priv,
> -				       enum transcoder cpu_transcoder);
> +void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state);
>  void intel_ddi_enable_pipe_clock(const struct intel_crtc_state *crtc_state);
>  void intel_ddi_disable_pipe_clock(const  struct intel_crtc_state *crtc_state);
>  void intel_ddi_set_pipe_settings(const struct intel_crtc_state *crtc_state);
> -- 
> 1.9.1
> 
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