Re: [PATCH] drm/gma500/cdv: Check vbt config bits when detecting lvds panels

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 16-04-19 13:46, Patrik Jakobsson wrote:
> Some machines have an lvds child device in vbt even though a panel is
> not attached. To make detection more reliable we now also check the lvds
> config bits available in the vbt.
> 
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1665766
> Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>

The reporter of https://bugzilla.redhat.com/show_bug.cgi?id=1665766
just got back to me and he confirms that this patch fixes the
false-positive LVDS panel detection on his NAS, without needing
a DMI blacklist.

So it looks like this patch indeed is a better fix then my initial
DMI blacklist approach and from my pov this patch is ready to
go upstream.

Regards,

Hans


> ---
>   drivers/gpu/drm/gma500/cdv_intel_lvds.c | 3 +++
>   drivers/gpu/drm/gma500/intel_bios.c     | 3 +++
>   drivers/gpu/drm/gma500/psb_drv.h        | 1 +
>   3 files changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/gma500/cdv_intel_lvds.c b/drivers/gpu/drm/gma500/cdv_intel_lvds.c
> index de9531caaca0..9c8446184b17 100644
> --- a/drivers/gpu/drm/gma500/cdv_intel_lvds.c
> +++ b/drivers/gpu/drm/gma500/cdv_intel_lvds.c
> @@ -594,6 +594,9 @@ void cdv_intel_lvds_init(struct drm_device *dev,
>   	int pipe;
>   	u8 pin;
>   
> +	if (!dev_priv->lvds_enabled_in_vbt)
> +		return;
> +
>   	pin = GMBUS_PORT_PANEL;
>   	if (!lvds_is_present_in_vbt(dev, &pin)) {
>   		DRM_DEBUG_KMS("LVDS is not present in VBT\n");
> diff --git a/drivers/gpu/drm/gma500/intel_bios.c b/drivers/gpu/drm/gma500/intel_bios.c
> index 63bde4e86c6a..e019ea271ffc 100644
> --- a/drivers/gpu/drm/gma500/intel_bios.c
> +++ b/drivers/gpu/drm/gma500/intel_bios.c
> @@ -436,6 +436,9 @@ parse_driver_features(struct drm_psb_private *dev_priv,
>   	if (driver->lvds_config == BDB_DRIVER_FEATURE_EDP)
>   		dev_priv->edp.support = 1;
>   
> +	dev_priv->lvds_enabled_in_vbt = driver->lvds_config != 0;
> +	DRM_DEBUG_KMS("LVDS VBT config bits: 0x%x\n", driver->lvds_config);
> +
>   	/* This bit means to use 96Mhz for DPLL_A or not */
>   	if (driver->primary_lfp_id)
>   		dev_priv->dplla_96mhz = true;
> diff --git a/drivers/gpu/drm/gma500/psb_drv.h b/drivers/gpu/drm/gma500/psb_drv.h
> index 941b238bdcc9..bc608ddc3bd1 100644
> --- a/drivers/gpu/drm/gma500/psb_drv.h
> +++ b/drivers/gpu/drm/gma500/psb_drv.h
> @@ -537,6 +537,7 @@ struct drm_psb_private {
>   	int lvds_ssc_freq;
>   	bool is_lvds_on;
>   	bool is_mipi_on;
> +	bool lvds_enabled_in_vbt;
>   	u32 mipi_ctrl_display;
>   
>   	unsigned int core_freq;
> 
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