Re: [PATCH v3 3/4] drm/bridge: ti-sn65dsi86: Read EDID blob over DDC

From: Stephen Boyd
Date: Mon Mar 22 2021 - 23:19:02 EST


Quoting Laurent Pinchart (2021-03-17 17:20:43)
> Hi Stephen,
>
> Reviving a bit of an old thread, for a question.
>
> On Mon, Nov 02, 2020 at 10:11:43AM -0800, Stephen Boyd wrote:
> > @@ -265,6 +267,23 @@ connector_to_ti_sn_bridge(struct drm_connector *connector)
> > static int ti_sn_bridge_connector_get_modes(struct drm_connector *connector)
> > {
> > struct ti_sn_bridge *pdata = connector_to_ti_sn_bridge(connector);
> > + struct edid *edid = pdata->edid;
> > + int num, ret;
> > +
> > + if (!edid) {
> > + pm_runtime_get_sync(pdata->dev);
> > + edid = pdata->edid = drm_get_edid(connector, &pdata->aux.ddc);
> > + pm_runtime_put(pdata->dev);
>
> Is there any specific reason to use the indirect access method, compared
> to the direct method that translates access to an I2C ancillary address
> to an I2C-over-AUX transaction (see page 20 of SLLSEH2B) ? The direct
> method seems it would be more efficient.
>

No I don't think it matters. I was just using the existing support code
that Sean wrote instead of digging into the details. Maybe Sean ran into
something earlier and abandoned that approach?