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

[Patrik Jakobsson]

On Sun, Apr 21, 2019 at 8:46 PM Hans de Goede <hdegoede at redhat.com> wrote:
>
> 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 at gmail.com>
> > Cc: Hans de Goede <hdegoede at redhat.com>
> > Cc: Ville Syrjälä <ville.syrjala at 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.

Thanks Hans, can I add your review tag?

>
> 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;
> >