[PATCH for drm-misc-fixes v3 1/2] drm/hisilicon/hibmc: Modify the method of obtaining the hpd_status
From: Yongbang Shi
Date: Thu Sep 24 2026 - 04:21:52 EST
From: Lin He <helin52@xxxxxxxxxx>
To more accurately determine whether the current HPD status matches the
interrupt status, the polling mechanism in the lower half of the HPD
interrupt (via hibmc_dp_check_hpd_status) has been replaced with directly
retrieving the interrupt status in the upper half of the interrupt (via
hibmc_dp_get_hpd_status).
* Detection and training are not performed if hpd_status is not HPD_IN.
* Set the initial status of hpd_status to HPD_OUT.
Fixes: 3906e7a3b26d ("drm/hisilicon/hibmc: fix dp probabilistical detect errors after HPD irq")
Signed-off-by: Lin He <helin52@xxxxxxxxxx>
Signed-off-by: Yongbang Shi <shiyongbang@xxxxxxxxxx>
---
ChangeLog:
v2 -> v3:
- Delete irq_status and use hpd_status directly for hotplug
detection. (sashiko-bot)
- Add debug logs when hpd_status is not HPD_IN in detect and
encoder_enable.
v1 -> v2:
- More states in HIBMC_DP_HPD_STATUS are added to the
'hibmc_dp_get_hpd_status'.
---
drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h | 1 -
drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c | 32 +++++++++++------
drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h | 5 +--
.../gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c | 34 +++++++++++--------
.../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 2 +-
5 files changed, 45 insertions(+), 29 deletions(-)
diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
index f53dac256ee0..b0e258b9265e 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
@@ -43,7 +43,6 @@ struct hibmc_dp_dev {
u8 downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
struct drm_dp_desc desc;
bool is_branch;
- int hpd_status;
void __iomem *serdes_base;
};
diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
index d5bd3c45649b..a4cd4cd8cc75 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
@@ -191,6 +191,10 @@ int hibmc_dp_hw_init(struct hibmc_dp *dp)
writel(HIBMC_DP_HDCP, dp_dev->base + HIBMC_DP_HDCP_CFG);
/* clock enable */
writel(HIBMC_DP_CLK_EN, dp_dev->base + HIBMC_DP_DPTX_CLK_CTRL);
+ /* To latch the HPD interrupt, ensuring that DP can support more modes
+ * within the fbcon framework when connected alone.
+ */
+ msleep(100);
return 0;
}
@@ -322,20 +326,26 @@ void hibmc_dp_set_cbar(struct hibmc_dp *dp, const struct hibmc_dp_cbar_cfg *cfg)
writel(HIBMC_DP_SYNC_EN_MASK, dp_dev->base + HIBMC_DP_TIMING_SYNC_CTRL);
}
-bool hibmc_dp_check_hpd_status(struct hibmc_dp *dp, int exp_status)
+int hibmc_dp_get_hpd_status(struct hibmc_dp *dp)
{
+ int hpd_status = HIBMC_HPD_UNKNOWN;
u32 status;
- int ret;
- ret = readl_poll_timeout(dp->dp_dev->base + HIBMC_DP_HPD_STATUS, status,
- FIELD_GET(HIBMC_DP_HPD_CUR_STATE, status) == exp_status,
- 1000, 100000); /* DP spec says 100ms */
- if (ret) {
- drm_dbg_dp(dp->drm_dev, "wait hpd status timeout");
- return false;
+ status = FIELD_GET(HIBMC_DP_HPD_CUR_STATE,
+ readl(dp->dp_dev->base + HIBMC_DP_HPD_STATUS));
+ switch (status) {
+ case 0: /* idle */
+ case 3: /* unplug */
+ case 4: /* unplug intermediate */
+ hpd_status = HIBMC_HPD_OUT;
+ break;
+ case 1: /* plug */
+ case 2: /* plug intermediate */
+ hpd_status = HIBMC_HPD_IN;
+ break;
+ default:
+ break;
}
- dp->dp_dev->hpd_status = exp_status;
-
- return true;
+ return hpd_status;
}
diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
index 0f3662d8737e..959bf95f6fe5 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
@@ -15,6 +15,7 @@
struct hibmc_dp_dev;
enum hibmc_hpd_status {
+ HIBMC_HPD_UNKNOWN,
HIBMC_HPD_OUT,
HIBMC_HPD_IN,
};
@@ -54,7 +55,7 @@ struct hibmc_dp {
void __iomem *mmio;
struct drm_dp_aux aux;
struct hibmc_dp_cbar_cfg cfg;
- u32 irq_status;
+ int hpd_status;
int phys_status;
};
@@ -66,7 +67,7 @@ void hibmc_dp_reset_link(struct hibmc_dp *dp);
void hibmc_dp_hpd_cfg(struct hibmc_dp *dp);
void hibmc_dp_enable_int(struct hibmc_dp *dp);
void hibmc_dp_disable_int(struct hibmc_dp *dp);
-bool hibmc_dp_check_hpd_status(struct hibmc_dp *dp, int exp_status);
+int hibmc_dp_get_hpd_status(struct hibmc_dp *dp);
u8 hibmc_dp_get_link_rate(struct hibmc_dp *dp);
u8 hibmc_dp_get_lanes(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 2e9403b8bf3c..1f8ea0b09253 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
@@ -15,8 +15,6 @@
#include "dp/dp_comm.h"
#include "dp/dp_config.h"
-#define DP_MASKED_SINK_HPD_PLUG_INT BIT(2)
-
static int hibmc_dp_connector_get_modes(struct drm_connector *connector)
{
const struct drm_edid *drm_edid;
@@ -63,11 +61,10 @@ static int hibmc_dp_detect(struct drm_connector *connector,
struct hibmc_dp_dev *dp_dev = dp->dp_dev;
int ret = connector_status_disconnected;
- if (dp->irq_status) {
- if (dp_dev->hpd_status != HIBMC_HPD_IN) {
- ret = connector_status_disconnected;
- goto exit;
- }
+ if (dp->hpd_status != HIBMC_HPD_IN) {
+ drm_dbg_dp(dp->drm_dev, "dp detect skipped, hpd (%d)\n",
+ dp->hpd_status);
+ goto exit;
}
if (!hibmc_dp_get_dpcd(dp_dev)) {
@@ -166,6 +163,12 @@ static void hibmc_dp_encoder_enable(struct drm_encoder *drm_encoder,
struct hibmc_dp *dp = container_of(drm_encoder, struct hibmc_dp, encoder);
struct drm_display_mode *mode = &drm_encoder->crtc->state->mode;
+ if (dp->hpd_status != HIBMC_HPD_IN) {
+ drm_dbg_dp(dp->drm_dev, "dp encoder enable skipped, hpd (%d)\n",
+ dp->hpd_status);
+ return;
+ }
+
if (hibmc_dp_prepare(dp, mode))
return;
@@ -189,24 +192,26 @@ 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);
- int idx, exp_status;
+ int status = priv->dp.hpd_status;
+ int idx;
if (!drm_dev_enter(dev, &idx))
return -ENODEV;
- if (priv->dp.irq_status & DP_MASKED_SINK_HPD_PLUG_INT) {
+ if (status == HIBMC_HPD_IN) {
drm_dbg_dp(&priv->dev, "HPD IN isr occur!\n");
hibmc_dp_hpd_cfg(&priv->dp);
- exp_status = HIBMC_HPD_IN;
- } else {
+ } else if (status == HIBMC_HPD_OUT) {
drm_dbg_dp(&priv->dev, "HPD OUT isr occur!\n");
hibmc_dp_reset_link(&priv->dp);
- exp_status = HIBMC_HPD_OUT;
+ } else {
+ drm_err(&priv->dev, "HPD status (%d) error\n", status);
+ goto exit;
}
- if (hibmc_dp_check_hpd_status(&priv->dp, exp_status))
- drm_connector_helper_hpd_irq_event(&priv->dp.connector);
+ drm_connector_helper_hpd_irq_event(&priv->dp.connector);
+exit:
drm_dev_exit(idx);
return IRQ_HANDLED;
@@ -223,6 +228,7 @@ int hibmc_dp_init(struct hibmc_drm_private *priv)
dp->mmio = priv->mmio;
dp->drm_dev = dev;
+ dp->hpd_status = HIBMC_HPD_OUT;
ret = hibmc_dp_hw_init(&priv->dp);
if (ret) {
diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
index 4d85c89f3f88..4ab0e565cb13 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
@@ -62,7 +62,7 @@ static irqreturn_t hibmc_dp_interrupt(int irq, void *arg)
status = readl(priv->mmio + HIBMC_DP_INTSTAT);
if (status) {
- priv->dp.irq_status = status;
+ priv->dp.hpd_status = hibmc_dp_get_hpd_status(&priv->dp);
writel(status, priv->mmio + HIBMC_DP_INTCLR);
return IRQ_WAKE_THREAD;
}
--
2.43.0