drm/i915/bios: use a flag for vbt hdmi level shift presence

The pre-initialized magic value is a bit silly, switch to a flag
instead.

v2: Reduce paranoia to a single sanity check (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/74fe24ab6d5f0ea2ff2059cdf044d6d3006080fc.1573227240.git.jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index a03f56b7b4ef445519c9db9ec60aa3f465bfe5be..c19b234bebe650b7c7aa66814136f7ac32e3c27e 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -1509,6 +1509,7 @@ static void parse_ddi_port(struct drm_i915_private *dev_priv,
                              port_name(port),
                              hdmi_level_shift);
                info->hdmi_level_shift = hdmi_level_shift;
+               info->hdmi_level_shift_set = true;
        }
 
        if (bdb_version >= 204) {
@@ -1692,8 +1693,6 @@ parse_general_definitions(struct drm_i915_private *dev_priv,
 static void
 init_vbt_defaults(struct drm_i915_private *dev_priv)
 {
-       enum port port;
-
        dev_priv->vbt.crt_ddc_pin = GMBUS_PIN_VGADDC;
 
        /* Default to having backlight */
@@ -1721,13 +1720,6 @@ init_vbt_defaults(struct drm_i915_private *dev_priv)
        dev_priv->vbt.lvds_ssc_freq = intel_bios_ssc_frequency(dev_priv,
                        !HAS_PCH_SPLIT(dev_priv));
        DRM_DEBUG_KMS("Set default to SSC at %d kHz\n", dev_priv->vbt.lvds_ssc_freq);
-
-       for_each_port(port) {
-               struct ddi_vbt_port_info *info =
-                       &dev_priv->vbt.ddi_port_info[port];
-
-               info->hdmi_level_shift = HDMI_LEVEL_SHIFT_UNKNOWN;
-       }
 }
 
 /* Defaults to initialize only if there is no VBT. */

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index a387aea1c80927063b65368c6ac2588e1596b325..e56eb8a49cdd6a49ae2c6d52054f3bc32df7b2e1 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -888,11 +888,10 @@ icl_get_combo_buf_trans(struct drm_i915_private *dev_priv, int type, int rate,
 
 static int intel_ddi_hdmi_level(struct drm_i915_private *dev_priv, enum port port)
 {
+       struct ddi_vbt_port_info *port_info = &dev_priv->vbt.ddi_port_info[port];
        int n_entries, level, default_entry;
        enum phy phy = intel_port_to_phy(dev_priv, port);
 
-       level = dev_priv->vbt.ddi_port_info[port].hdmi_level_shift;
-
        if (INTEL_GEN(dev_priv) >= 12) {
                if (intel_phy_is_combo(dev_priv, phy))
                        icl_get_combo_buf_trans(dev_priv, INTEL_OUTPUT_HDMI,
@@ -927,12 +926,14 @@ static int intel_ddi_hdmi_level(struct drm_i915_private *dev_priv, enum port por
                return 0;
        }
 
-       /* Choose a good default if VBT is badly populated */
-       if (level == HDMI_LEVEL_SHIFT_UNKNOWN || level >= n_entries)
-               level = default_entry;
-
        if (WARN_ON_ONCE(n_entries == 0))
                return 0;
+
+       if (port_info->hdmi_level_shift_set)
+               level = port_info->hdmi_level_shift;
+       else
+               level = default_entry;
+
        if (WARN_ON_ONCE(level >= n_entries))
                level = n_entries - 1;
 

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index b82ff0bc6d0c934bd9c48608095c4756430fc920..9d95125f17980b4a498e5ba7be8729f90a606a2c 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -627,13 +627,9 @@ struct ddi_vbt_port_info {
 
        int max_tmds_clock;
 
-       /*
-        * This is an index in the HDMI/DVI DDI buffer translation table.
-        * The special value HDMI_LEVEL_SHIFT_UNKNOWN means the VBT didn't
-        * populate this field.
-        */
-#define HDMI_LEVEL_SHIFT_UNKNOWN       0xff
+       /* This is an index in the HDMI/DVI DDI buffer translation table. */
        u8 hdmi_level_shift;
+       u8 hdmi_level_shift_set:1;
 
        u8 supports_dvi:1;
        u8 supports_hdmi:1;