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Subject[PATCH v2 3/5] 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 <>
Signed-off-by: Hans de Goede <>
drivers/gpu/drm/i915/display/intel_dsi.h | 2 +-
drivers/gpu/drm/i915/display/intel_dsi_vbt.c | 7 +++----
drivers/gpu/drm/i915/display/vlv_dsi.c | 4 +++-
3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dsi.h b/drivers/gpu/drm/i915/display/intel_dsi.h
index de7e51cd3460..675771ea91aa 100644
--- a/drivers/gpu/drm/i915/display/intel_dsi.h
+++ b/drivers/gpu/drm/i915/display/intel_dsi.h
@@ -203,7 +203,7 @@ void bxt_dsi_reset_clocks(struct intel_encoder *encoder, enum port port);

/* intel_dsi_vbt.c */
bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id);
-void intel_dsi_vbt_gpio_init(struct intel_dsi *intel_dsi);
+void intel_dsi_vbt_gpio_init(struct intel_dsi *intel_dsi, bool panel_is_on);
void intel_dsi_vbt_gpio_cleanup(struct intel_dsi *intel_dsi);
void intel_dsi_vbt_exec_sequence(struct intel_dsi *intel_dsi,
enum mipi_seq seq_id);
diff --git a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
index 8be7d6c507aa..4210f449553e 100644
--- a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
+++ b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
@@ -688,17 +688,16 @@ bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id)
* On some BYT/CHT devs some sequences are incomplete and we need to manually
* control some GPIOs.
-void intel_dsi_vbt_gpio_init(struct intel_dsi *intel_dsi)
+void intel_dsi_vbt_gpio_init(struct intel_dsi *intel_dsi, bool panel_is_on)
struct drm_device *dev = intel_dsi->;
struct drm_i915_private *dev_priv = to_i915(dev);
struct mipi_config *mipi_config = dev_priv->vbt.dsi.config;
+ enum gpiod_flags flags = panel_is_on ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;

if ((IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) &&
mipi_config->pwm_blc == PPS_BLC_PMIC) {
- intel_dsi->gpio_panel =
- gpiod_get(dev->dev, "panel", GPIOD_OUT_HIGH);
+ intel_dsi->gpio_panel = gpiod_get(dev->dev, "panel", flags);
if (IS_ERR(intel_dsi->gpio_panel)) {
DRM_ERROR("Failed to own gpio for panel control\n");
intel_dsi->gpio_panel = NULL;
diff --git a/drivers/gpu/drm/i915/display/vlv_dsi.c b/drivers/gpu/drm/i915/display/vlv_dsi.c
index c1edd8857af0..d0efee09c593 100644
--- a/drivers/gpu/drm/i915/display/vlv_dsi.c
+++ b/drivers/gpu/drm/i915/display/vlv_dsi.c
@@ -1759,6 +1759,7 @@ 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;


@@ -1857,7 +1858,8 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)


- 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,
 \ /
  Last update: 2019-12-16 21:52    [W:2.108 / U:0.008 seconds]
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