On Thu, Aug 14, 2025 at 08:19:41PM +0800, Yongbang Shi wrote:
>
> > On Wed, Aug 13, 2025 at 05:42:29PM +0800, Yongbang Shi wrote:
> > > From: Baihan Li <libai...@huawei.com>
> > >
> > > The debouncing when HPD pulled out still remains sometimes, 200ms still
> > > can
> > > not ensure helper_detect() is correct. So add a flag to hold the sink
> > > status, and changed detect_ctx() functions by using flag to check status.
> > THis doesn't explain what is wrong with
> > drm_connector_helper_detect_from_ddc(). In the end, this function
> > doesn't use the HPD pin.
>
> I'm sorry about the misunderstanding.
> The issue is that after plugging or unplugging the monitor, the driver takes
> no action sometimes
> even though an interrupt is triggered. The root cause is that
> drm_connector_helper_detect_from_ddc()
> still returns connected status when the monitor is unplugged.
> And I will fix the way in the end.
Can you perform a normal DP detection: read DPCD and check that there is
a DPRX attached and that it's either non-branch device or it has one or
more sinks?
>
> Thanks,
> Baihan Li!
>
>
> > > Fixes: 3c7623fb5bb6 ("drm/hisilicon/hibmc: Enable this hot plug detect of
> > > irq feature")
> > > Signed-off-by: Baihan Li <libai...@huawei.com>
> > > Signed-off-by: Yongbang Shi <shiyongb...@huawei.com>
> > > ---
> > > ChangeLog:
> > > v3 -> v4:
> > > - remove link training process in hibmc_dp_detect(), suggested by
> > > Dmitry Baryshkov.
> > > - remove if (dev->registered), suggested by Dmitry Baryshkov.
> > > ---
> > > drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h | 1 +
> > > .../gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c | 19 ++++++++++++-------
> > > 2 files changed, 13 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
> > > b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
> > > index 665f5b166dfb..68867475508c 100644
> > > --- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
> > > +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
> > > @@ -50,6 +50,7 @@ struct hibmc_dp {
> > > struct drm_dp_aux aux;
> > > struct hibmc_dp_cbar_cfg cfg;
> > > u32 irq_status;
> > > + int hpd_status;
> > > };
> > > int hibmc_dp_hw_init(struct hibmc_dp *dp);
> > > diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
> > > b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
> > > index d06832e62e96..ded38530ecda 100644
> > > --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
> > > +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
> > > @@ -34,9 +34,12 @@ static int hibmc_dp_connector_get_modes(struct
> > > drm_connector *connector)
> > > static int hibmc_dp_detect(struct drm_connector *connector,
> > > struct drm_modeset_acquire_ctx *ctx, bool
> > > force)
> > > {
> > > - mdelay(200);
> > > + struct hibmc_dp *dp = to_hibmc_dp(connector);
> > > - return drm_connector_helper_detect_from_ddc(connector, ctx, force);
> > > + if (dp->hpd_status)
> > > + return connector_status_connected;
> > > + else
> > > + return connector_status_disconnected;
> > > }
> > > static const struct drm_connector_helper_funcs
> > > hibmc_dp_conn_helper_funcs = {
> > > @@ -115,21 +118,23 @@ irqreturn_t hibmc_dp_hpd_isr(int irq, void *arg)
> > > {
> > > struct drm_device *dev = (struct drm_device *)arg;
> > > struct hibmc_drm_private *priv = to_hibmc_drm_private(dev);
> > > + struct hibmc_dp *dp = &priv->dp;
> > > int idx;
> > > if (!drm_dev_enter(dev, &idx))
> > > return -ENODEV;
> > > - if (priv->dp.irq_status & DP_MASKED_SINK_HPD_PLUG_INT) {
> > > + if (((dp->irq_status & DP_MASKED_SINK_HPD_PLUG_INT) &&
> > > !dp->hpd_status)) {
> > > drm_dbg_dp(&priv->dev, "HPD IN isr occur!\n");
> > > - hibmc_dp_hpd_cfg(&priv->dp);
> > > + hibmc_dp_hpd_cfg(dp);
> > > + dp->hpd_status = 1;
> > > } else {
> > > drm_dbg_dp(&priv->dev, "HPD OUT isr occur!\n");
> > > - hibmc_dp_reset_link(&priv->dp);
> > > + hibmc_dp_reset_link(dp);
> > > + dp->hpd_status = 0;
> > > }
> > > - if (dev->registered)
> > > - drm_connector_helper_hpd_irq_event(&priv->dp.connector);
> > > + drm_connector_helper_hpd_irq_event(&priv->dp.connector);
> > > drm_dev_exit(idx);
> > > --
> > > 2.33.0
> > >
--
With best wishes
Dmitry
