drm: tda998x: Fix EDID read timeout on HDMI connect

When the HDMI cable is disconnected and reconnected, EDID reading
is called too early raising a EDID read timeout.
This patch uses the system work queue to delay the notification
of the HDMI connect/disconnect event.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index 6795f094f737..98f3c4dd7375 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -33,6 +33,7 @@ struct tda998x_priv {
         struct i2c_client *cec;
         struct i2c_client *hdmi;
         struct mutex mutex;
+        struct delayed_work dwork;
         uint16_t rev;
         uint8_t current_page;
         int dpms;
@@ -549,6 +550,17 @@ tda998x_reset(struct tda998x_priv *priv)
         reg_write(priv, REG_MUX_VP_VIP_OUT, 0x24);
 }
 
+/* handle HDMI connect/disconnect */
+static void tda998x_hpd(struct work_struct *work)
+{
+        struct delayed_work *dwork = to_delayed_work(work);
+        struct tda998x_priv *priv =
+                        container_of(dwork, struct tda998x_priv, dwork);
+
+        if (priv->encoder && priv->encoder->dev)
+                drm_kms_helper_hotplug_event(priv->encoder->dev);
+}
+
 /*
  * only 2 interrupts may occur: screen plug/unplug and EDID read
  */
@@ -572,8 +584,7 @@ static irqreturn_t tda998x_irq_thread(int irq, void *data)
                 priv->wq_edid_wait = 0;
                 wake_up(&priv->wq_edid);
         } else if (cec != 0) {                  /* HPD change */
-                if (priv->encoder && priv->encoder->dev)
-                        drm_helper_hpd_irq_event(priv->encoder->dev);
+                schedule_delayed_work(&priv->dwork, HZ/10);
         }
         return IRQ_HANDLED;
 }
@@ -1183,8 +1194,10 @@ static void tda998x_destroy(struct tda998x_priv *priv)
         /* disable all IRQs and free the IRQ handler */
         cec_write(priv, REG_CEC_RXSHPDINTENA, 0);
         reg_clear(priv, REG_INT_FLAGS_2, INT_FLAGS_2_EDID_BLK_RD);
-        if (priv->hdmi->irq)
+        if (priv->hdmi->irq) {
                 free_irq(priv->hdmi->irq, priv);
+                cancel_delayed_work_sync(&priv->dwork);
+        }
 
         i2c_unregister_device(priv->cec);
 }
@@ -1338,8 +1351,9 @@ static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
         if (client->irq) {
                 int irqf_trigger;
 
-                /* init read EDID waitqueue */
+                /* init read EDID waitqueue and HDP work */
                 init_waitqueue_head(&priv->wq_edid);
+                INIT_DELAYED_WORK(&priv->dwork, tda998x_hpd);
 
                 /* clear pending interrupts */
                 reg_read(priv, REG_INT_FLAGS_0);