Re: [Intel-gfx] [PATCH 1/4] drm/i915: Skip some timing checks on BXT/GLK DSI transcoders

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

On Mon, 27 Nov 2023, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Apparently some BXT/GLK systems have DSI panels whose timings
> don't agree with the normal cpu transcoder hblank>=32 limitation.
> This is perhaps fine as there are no specific hblank/etc. limits
> listed for the BXT/GLK DSI transcoders.
>
> Move those checks out from the global intel_mode_valid() into
> into connector specific .mode_valid() hooks, skipping BXT/GLK
> DSI connectors. We'll leave the basic [hv]display/[hv]total
> checks in intel_mode_valid() as those seem like sensible upper
> limits regardless of the transcoder used.
>
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9720
> Fixes: 8f4b1068e7fc ("drm/i915: Check some transcoder timing minimum limits")
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/icl_dsi.c       |  7 +++++++
>  drivers/gpu/drm/i915/display/intel_crt.c     |  5 +++++
>  drivers/gpu/drm/i915/display/intel_display.c | 10 ++++++++++
>  drivers/gpu/drm/i915/display/intel_display.h |  3 +++
>  drivers/gpu/drm/i915/display/intel_dp.c      |  4 ++++
>  drivers/gpu/drm/i915/display/intel_dp_mst.c  |  4 ++++
>  drivers/gpu/drm/i915/display/intel_dvo.c     |  6 ++++++
>  drivers/gpu/drm/i915/display/intel_hdmi.c    |  4 ++++
>  drivers/gpu/drm/i915/display/intel_lvds.c    |  5 +++++
>  drivers/gpu/drm/i915/display/intel_sdvo.c    |  8 +++++++-
>  drivers/gpu/drm/i915/display/intel_tv.c      |  8 +++++++-
>  drivers/gpu/drm/i915/display/vlv_dsi.c       | 18 +++++++++++++++++-
>  12 files changed, 79 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
> index 481fcb650850..ac456a2275db 100644
> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> @@ -1440,6 +1440,13 @@ static void gen11_dsi_post_disable(struct intel_atomic_state *state,
>  static enum drm_mode_status gen11_dsi_mode_valid(struct drm_connector *connector,
>  						 struct drm_display_mode *mode)
>  {
> +	struct drm_i915_private *i915 = to_i915(connector->dev);
> +	enum drm_mode_status status;
> +
> +	status = intel_cpu_transcoder_mode_valid(i915, mode);
> +	if (status != MODE_OK)
> +		return status;
> +
>  	/* FIXME: DSC? */
>  	return intel_dsi_mode_valid(connector, mode);
>  }
> diff --git a/drivers/gpu/drm/i915/display/intel_crt.c b/drivers/gpu/drm/i915/display/intel_crt.c
> index 0e33a0523a75..abaacea5c2cc 100644
> --- a/drivers/gpu/drm/i915/display/intel_crt.c
> +++ b/drivers/gpu/drm/i915/display/intel_crt.c
> @@ -348,8 +348,13 @@ intel_crt_mode_valid(struct drm_connector *connector,
>  	struct drm_device *dev = connector->dev;
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	int max_dotclk = dev_priv->max_dotclk_freq;
> +	enum drm_mode_status status;
>  	int max_clock;
>  
> +	status = intel_cpu_transcoder_mode_valid(dev_priv, mode);
> +	if (status != MODE_OK)
> +		return status;
> +
>  	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
>  		return MODE_NO_DBLESCAN;
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 5cf162628b95..23b077f43614 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -7734,6 +7734,16 @@ enum drm_mode_status intel_mode_valid(struct drm_device *dev,
>  	    mode->vtotal > vtotal_max)
>  		return MODE_V_ILLEGAL;
>  
> +	return MODE_OK;
> +}
> +
> +enum drm_mode_status intel_cpu_transcoder_mode_valid(struct drm_i915_private *dev_priv,
> +						     const struct drm_display_mode *mode)
> +{

Overall the patch looks fine, even if it's a bit meh we have to
duplicate the calls so much. No way around that I guess.

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

But please explain the intel_cpu_transcoder_mode_valid() naming. I'm not
sure I follow.



-- 
Jani Nikula, Intel