drm/i915/dsi: Init panel-enable GPIO to low when the LCD is initially off (v2)

When the LCD has not been turned on by the firmware/GOP, because e.g. the
device was booted with an external monitor connected over HDMI, we should
not turn on the panel-enable GPIO when we request it.

Turning on the panel-enable GPIO when we request it, means we turn it on
too early in the init-sequence, which causes some panels to not correctly
light up.

This commits adds a panel_is_on parameter to intel_dsi_vbt_gpio_init()
and makes intel_dsi_vbt_gpio_init() set the initial GPIO value accordingly.

This fixes the panel not lighting up on a Thundersoft TST168 tablet when
booted with an external monitor connected over HDMI.

Changes in v2:
- Call intel_dsi_get_hw_state() to check if the panel is on instead of
  relying on the current_mode pointer

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191216205122.1850923-4-hdegoede@redhat.com

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/display/vlv_dsi.c b/drivers/gpu/drm/i915/display/vlv_dsi.c
index a20b7d81a72f..bd368a023cd9 100644
--- a/drivers/gpu/drm/i915/display/vlv_dsi.c
+++ b/drivers/gpu/drm/i915/display/vlv_dsi.c
@@ -1815,6 +1815,7 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
 	struct drm_connector *connector;
 	struct drm_display_mode *current_mode, *fixed_mode;
 	enum port port;
+	enum pipe pipe;
 
 	DRM_DEBUG_KMS("\n");
 
@@ -1913,7 +1914,8 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
 
 	vlv_dphy_param_init(intel_dsi);
 
-	intel_dsi_vbt_gpio_init(intel_dsi);
+	intel_dsi_vbt_gpio_init(intel_dsi,
+				intel_dsi_get_hw_state(intel_encoder, &pipe));
 
 	drm_connector_init(dev, connector, &intel_dsi_connector_funcs,
 			   DRM_MODE_CONNECTOR_DSI);