Re: [PATCH 3/5] drm/i915/dsi: Init panel-enable GPIO to low when the LCD is initially off

[Hans de Goede]

Hi,

On 16-12-2019 15:14, Ville Syrjälä wrote:
> On Mon, Dec 16, 2019 at 02:51:54PM +0100, Hans de Goede wrote:
> > Hi,
> >
> > Thank you for the reviews.
> >
> > On 16-12-2019 14:45, Ville Syrjälä wrote:
> > > On Sun, Dec 15, 2019 at 05:38:08PM +0100, Hans de Goede wrote:
> > > > 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.
> > > >
> > > > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> > > > ---
> > > >    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       | 2 +-
> > > >    3 files changed, 5 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 5352e8c9eca5..027970348b22 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->base.base.dev;
> > > >    	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;
> > >
> > > Can't we just tell it not to change the current setting?
> >
> > We could use GPIOD_ASIS for that, but with the SoC pins (when the PMIC is
> > not used for backlight control) things get a bit muddy, I've seen several
> > instances of this message from drivers/pinctrl/intel/pinctrl-baytrail.c
> > trigger when the GOP did not init the panel:
> >
> > dev_warn(vg->dev, FW_BUG "pin %u forcibly re-configured as GPIO\n", offset);
> >
> > And in that case with GPIOD_ASIS I have no idea which we initially get,
> > so this approach, where we clearly define which initial value we want,
> > seems better.
>
> I suppose. Probably better to not abuse the current_mode pointer for
> that though and just explicitly call encoder->get_hw_state() instead.

Ok, I'll fix this for v2 of the patch-set.

Regards,

Hans





> > p.s.
> >
> > The intel-gfx CI seems to seriously dislike my patches lately, almost
> > always failing them; and usually on what at least seem to be unrelated
> > test-cases. Any advice on how to deal with this?
>
> Yeah, CI is snafu. I keep smashing retest until it gets through BAT
> and then just double check the shard results to make sure nothing
> relevant has tripped. If things look OK I recommend replying to the
> result mail and provide a few short log snippets/other details on
> what failed so that it's clear that it's irrelevant.
>
> > > >    
> > > >    	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 178d0fffba5b..e86e4a11e199 100644
> > > > --- a/drivers/gpu/drm/i915/display/vlv_dsi.c
> > > > +++ b/drivers/gpu/drm/i915/display/vlv_dsi.c
> > > > @@ -1910,7 +1910,7 @@ 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, current_mode != NULL);
> > > >    
> > > >    	drm_connector_init(dev, connector, &intel_dsi_connector_funcs,
> > > >    			   DRM_MODE_CONNECTOR_DSI);
> > > > --
> > > > 2.23.0