Re: [Intel-gfx] [PATCH] drm/i915/sdvo: Fallback to current output timings for LVDS fixed mode

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 25 Oct 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> If we can't dig out a fixed mode for LVDS from the VBT or EDID
> let's fall back to using the current output timings. This should
> work as long as the BIOS has (somehow) enabled the output.
>
> In this case we are dealing with the some kind of BLB based POS
> machine (Toshiba SurePOS 500) where neither the OpRegion mailbox
> nor the vbios ROM contain a valid VBT. And no EDID anywhere we
> could find either.
>
> Cc: <stable@vger.kernel.org> # v5.19+
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7301
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

But they're saying it's a regression between 4.19 and 5.10...


> ---
>  drivers/gpu/drm/i915/display/intel_panel.c |  6 ++--
>  drivers/gpu/drm/i915/display/intel_panel.h |  3 ++
>  drivers/gpu/drm/i915/display/intel_sdvo.c  | 40 ++++++++++++++++++++++
>  3 files changed, 46 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
> index 69ce77711b7c..69082fbc7647 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.c
> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
> @@ -275,9 +275,9 @@ void intel_panel_add_edid_fixed_modes(struct intel_connector *connector,
>  	intel_panel_destroy_probed_modes(connector);
>  }
>  
> -static void intel_panel_add_fixed_mode(struct intel_connector *connector,
> -				       struct drm_display_mode *fixed_mode,
> -				       const char *type)
> +void intel_panel_add_fixed_mode(struct intel_connector *connector,
> +				struct drm_display_mode *fixed_mode,
> +				const char *type)
>  {
>  	struct drm_i915_private *i915 = to_i915(connector->base.dev);
>  	struct drm_display_info *info = &connector->base.display_info;
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.h b/drivers/gpu/drm/i915/display/intel_panel.h
> index 5c5b5b7f95b6..964efed8ef3c 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.h
> +++ b/drivers/gpu/drm/i915/display/intel_panel.h
> @@ -43,6 +43,9 @@ int intel_panel_fitting(struct intel_crtc_state *crtc_state,
>  			const struct drm_connector_state *conn_state);
>  int intel_panel_compute_config(struct intel_connector *connector,
>  			       struct drm_display_mode *adjusted_mode);
> +void intel_panel_add_fixed_mode(struct intel_connector *connector,
> +				struct drm_display_mode *fixed_mode,
> +				const char *type);
>  void intel_panel_add_edid_fixed_modes(struct intel_connector *connector,
>  				      bool use_alt_fixed_modes);
>  void intel_panel_add_vbt_lfp_fixed_mode(struct intel_connector *connector);
> diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
> index cf8e80936d8e..9ed54118b669 100644
> --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
> @@ -781,6 +781,13 @@ static bool intel_sdvo_get_input_timing(struct intel_sdvo *intel_sdvo,
>  				     SDVO_CMD_GET_INPUT_TIMINGS_PART1, dtd);
>  }
>  
> +static bool intel_sdvo_get_output_timing(struct intel_sdvo *intel_sdvo,
> +					 struct intel_sdvo_dtd *dtd)
> +{
> +	return intel_sdvo_get_timing(intel_sdvo,
> +				     SDVO_CMD_GET_OUTPUT_TIMINGS_PART1, dtd);
> +}
> +
>  static bool
>  intel_sdvo_create_preferred_input_timing(struct intel_sdvo *intel_sdvo,
>  					 struct intel_sdvo_connector *intel_sdvo_connector,
> @@ -2864,6 +2871,36 @@ intel_sdvo_analog_init(struct intel_sdvo *intel_sdvo, int device)
>  	return true;
>  }
>  
> +static void
> +intel_sdvo_add_current_fixed_mode(struct intel_sdvo *intel_sdvo,
> +				  struct intel_sdvo_connector *connector)
> +{
> +	struct drm_i915_private *i915 = to_i915(intel_sdvo->base.base.dev);
> +	struct drm_display_mode *mode;
> +	struct intel_sdvo_dtd dtd = {};
> +
> +	if (!intel_sdvo_set_target_output(intel_sdvo,
> +					  connector->output_flag)) {
> +		drm_dbg_kms(&i915->drm, "failed to set SDVO target output\n");
> +		return;
> +	}
> +
> +	if (!intel_sdvo_get_output_timing(intel_sdvo, &dtd)) {
> +		drm_dbg_kms(&i915->drm, "failed to get SDVO output timings\n");
> +		return;
> +	}
> +
> +	mode = drm_mode_create(&i915->drm);
> +	if (!mode)
> +		return;
> +
> +	intel_sdvo_get_mode_from_dtd(mode, &dtd);
> +
> +	drm_mode_set_name(mode);
> +
> +	intel_panel_add_fixed_mode(&connector->base, mode, "current (SDVO)");
> +}
> +
>  static bool
>  intel_sdvo_lvds_init(struct intel_sdvo *intel_sdvo, int device)
>  {
> @@ -2913,6 +2950,9 @@ intel_sdvo_lvds_init(struct intel_sdvo *intel_sdvo, int device)
>  		intel_panel_add_edid_fixed_modes(intel_connector, false);
>  	}
>  
> +	if (!intel_panel_preferred_fixed_mode(intel_connector))
> +		intel_sdvo_add_current_fixed_mode(intel_sdvo, intel_sdvo_connector);
> +
>  	intel_panel_init(intel_connector);
>  
>  	if (!intel_panel_preferred_fixed_mode(intel_connector))

-- 
Jani Nikula, Intel Open Source Graphics Center