[PATCH 1/2] drm/i915: Prevent HW access during init from SDVO TV get_modes hook

[Hogander, Jouni]

On Wed, 2024-02-07 at 15:26 +0200, Hogander, Jouni wrote:
> On Tue, 2024-02-06 at 17:39 +0200, Imre Deak wrote:
> > Prevent accessing the HW from the SDVO/TV get_modes connector hook.
> > Returning 0 from the hook will make the caller -
> > drm_helper_probe_single_connector_modes() - keep the previously
> > detected
> > mode list of the connector.
> 
> I don't see where this is done? Not sure if looking at wrong place,
> but
> I see it tries using some override edid and in case that fails as
> well
> uses drm_add_modes_noedid?
> 
> > 
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_sdvo.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c
> > b/drivers/gpu/drm/i915/display/intel_sdvo.c
> > index 2571ef5a1b211..ccea0efbd136f 100644
> > --- a/drivers/gpu/drm/i915/display/intel_sdvo.c
> > +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
> > @@ -2287,6 +2287,7 @@ static const struct drm_display_mode
> > sdvo_tv_modes[] = {
> >  static int intel_sdvo_get_tv_modes(struct drm_connector
> > *connector)
> 
> I see intel_sdvo_get_tv_modes is called from intel_sdvo_get_modes.
> Why
> there is no need to do the same in intel_sdvo_get_lvds_modes and
> intel_sdvo_get_ddc_modes as well?

It seems you are taking care of intel_svdo_get_ddc_modes in next patch.
Intel_svdo_get_lvds_modes doesn't touch the hw -> nothing to do there.

> 
> BR,
> 
> Jouni Högander
> 
> >  {
> >         struct intel_sdvo *intel_sdvo =
> > intel_attached_sdvo(to_intel_connector(connector));
> > +       struct drm_i915_private *i915 = to_i915(intel_sdvo-
> > > base.base.dev);
> >         struct intel_sdvo_connector *intel_sdvo_connector =
> >                 to_intel_sdvo_connector(connector);
> >         const struct drm_connector_state *conn_state = connector-
> > > state;
> > @@ -2298,6 +2299,9 @@ static int intel_sdvo_get_tv_modes(struct
> > drm_connector *connector)
> >         DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
> >                       connector->base.id, connector->name);
> >  
> > +       if (!intel_display_driver_check_access(i915))
> > +               return 0;
> > +
> >         /*
> >          * Read the list of supported input resolutions for the
> > selected TV
> >          * format.
>