On Mon, 24 Feb 2025 at 16:03, Yongbang Shi <shiyongbang@xxxxxxxxxx> wrote:
>
> > On Sat, Feb 22, 2025 at 06:35:48PM +0800, Yongbang Shi wrote:
> >>>> +static int hibmc_dp_hpd_event(struct drm_client_dev *client)
> >>>> +{
> >>>> + struct hibmc_dp *dp = container_of(client, struct hibmc_dp, client);
> >>>> + struct hibmc_drm_private *priv = to_hibmc_drm_private(dp->drm_dev);
> >>>> + struct drm_display_mode *mode = &priv->crtc.state->adjusted_mode;
> >>>> + int ret;
> >>>> +
> >>>> + if (dp->hpd_status) {
> >>>> + hibmc_dp_hpd_cfg(&priv->dp);
> >>>> + ret = hibmc_dp_prepare(dp, mode);
> >>>> + if (ret)
> >>>> + return ret;
> >>>> +
> >>>> + hibmc_dp_display_en(dp, true);
> >>>> + } else {
> >>>> + hibmc_dp_display_en(dp, false);
> >>>> + hibmc_dp_reset_link(&priv->dp);
> >>>> + }
> >>> If I understand this correctly, you are using a separate drm_client to
> >>> enable and disable the link & display. Why is it necessary? Existing
> >>> drm_clients and userspace compositors use drm framework, they should be
> >>> able to turn the display on and off as required.
> >>>
> >> Thanks for your asking, there are cfg/reset process when the connector 's pluging in/out.
> >> We want to cfg DP registers again when the connector changes. Not only dp link training, but also cfg
> >> the different video modes into DP registers.
> > Why? The link training and mode programming should happen during
> > pre_enable / enable stage (legacy or atomic).
>
> Hi Dmitry,
>
> Right, that's what I'm curious about. It won't call encoder enble/disable functions when I triggered HPD.
> And I'm sure the drm_connector_helper_hpd_irq_event() is called. So I add a drm_client for it.I
It should be userspace, who triggers the enable/disable (or it should
be the in-kernel fbdev / fbcon, which interface through the generic
drm_fbdev client).
--
With best wishes
Dmitry
