[PATCH v4 drm-dp 02/11] drm/hisilicon/hibmc: fix dp probabilistical detect errors after HPD irq

[Yongbang Shi]

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.

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