drm/hisilicon/hibmc: fix dp probabilistical detect errors after HPD irq

The issue is that drm_connector_helper_detect_from_ddc() returns wrong
status when plugging or unplugging the monitor, which may cause the link
failed err.[0] Use HPD pin status in DP's detect_ctx() for real physical
monitor in/out, and implement a complete DP detection including read DPCD,
check if it's a branch device and its sink count for different situations.

[0]:
	hibme-drm 0000:83:00.0: [drm] *ERROR* channel equalization failed 5 times
	hibme-drm 0000:83:00.0: [drm] *ERROR* channel equalization failed 5 times
	hibme-drm 0000:83:00.0: [drm] *ERROR* dp link training failed, ret: -16
	hibmc-drm 0000:83:00.0: [drm] *ERROR* hibme dp mode set failed: -16

Fixes: 3c7623fb5bb6 ("drm/hisilicon/hibmc: Enable this hot plug detect of irq feature")
Signed-off-by: Baihan Li <libaihan@huawei.com>
Signed-off-by: Yongbang Shi <shiyongbang@huawei.com>
Reviewed-by: Tao Tian <tiantao6@hisilicon.com>
Link: https://patch.msgid.link/20251210023759.3944834-2-shiyongbang@huawei.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
index 4add05c7f161a08b8c301ec1d4143f0fabd7d605..f9ee7ebfec55c30b3180b3386c860b1aaefce130 100644 (file)
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
@@ -40,6 +40,10 @@ struct hibmc_dp_dev {
        struct mutex lock; /* protects concurrent RW in hibmc_dp_reg_write_field() */
        struct hibmc_dp_link link;
        u8 dpcd[DP_RECEIVER_CAP_SIZE];
+       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 8f0daec7d174905ca7aa899e7f2201fc27846713..0ec6ace2d082285686939bac086b49227ea529f6 100644 (file)
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
@@ -2,6 +2,7 @@
 // Copyright (c) 2024 Hisilicon Limited.
 
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/delay.h>
 #include "dp_config.h"
 #include "dp_comm.h"
@@ -305,3 +306,21 @@ void hibmc_dp_set_cbar(struct hibmc_dp *dp, const struct hibmc_dp_cbar_cfg *cfg)
        hibmc_dp_reg_write_field(dp_dev, HIBMC_DP_COLOR_BAR_CTRL, BIT(0), cfg->enable);
        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)
+{
+       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;
+       }
+
+       dp->dp_dev->hpd_status = exp_status;
+
+       return true;
+}

diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
index 665f5b166dfb5cf199e65cddc8d786d68d3b1d1a..59c1eae153c55d82d8651be02c2c0ea42bf4e490 100644 (file)
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h
@@ -14,6 +14,11 @@
 
 struct hibmc_dp_dev;
 
+enum hibmc_hpd_status {
+       HIBMC_HPD_OUT,
+       HIBMC_HPD_IN,
+};
+
 enum hibmc_dp_cbar_pattern {
        CBAR_COLOR_BAR,
        CBAR_WHITE,
@@ -60,5 +65,6 @@ 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);
 
 #endif

diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
index 394b1e933c3ae70b33fb7154dbb4027385ceb64b..64306abcd986660b03aa1ac35a803208aa677643 100644 (file)
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
@@ -24,6 +24,9 @@
 #define HIBMC_DP_CFG_AUX_READY_DATA_BYTE       GENMASK(16, 12)
 #define HIBMC_DP_CFG_AUX                       GENMASK(24, 17)
 
+#define HIBMC_DP_HPD_STATUS                    0x98
+#define HIBMC_DP_HPD_CUR_STATE         GENMASK(7, 4)
+
 #define HIBMC_DP_PHYIF_CTRL0                   0xa0
 #define HIBMC_DP_CFG_SCRAMBLE_EN               BIT(0)
 #define HIBMC_DP_CFG_PAT_SEL                   GENMASK(7, 4)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
index d06832e62e966ef90059f357d5e8c854cb9346d1..4a66a107900a10c33b554dbab8ed67760392fc7e 100644 (file)
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c
@@ -12,6 +12,7 @@
 
 #include "hibmc_drm_drv.h"
 #include "dp/dp_hw.h"
+#include "dp/dp_comm.h"
 
 #define DP_MASKED_SINK_HPD_PLUG_INT    BIT(2)
 
@@ -31,12 +32,53 @@ static int hibmc_dp_connector_get_modes(struct drm_connector *connector)
        return count;
 }
 
+static bool hibmc_dp_get_dpcd(struct hibmc_dp_dev *dp_dev)
+{
+       int ret;
+
+       ret = drm_dp_read_dpcd_caps(dp_dev->aux, dp_dev->dpcd);
+       if (ret)
+               return false;
+
+       dp_dev->is_branch = drm_dp_is_branch(dp_dev->dpcd);
+
+       ret = drm_dp_read_desc(dp_dev->aux, &dp_dev->desc, dp_dev->is_branch);
+       if (ret)
+               return false;
+
+       ret = drm_dp_read_downstream_info(dp_dev->aux, dp_dev->dpcd, dp_dev->downstream_ports);
+       if (ret)
+               return false;
+
+       return true;
+}
+
 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);
+       struct hibmc_dp_dev *dp_dev = dp->dp_dev;
+       int ret;
+
+       if (dp->irq_status) {
+               if (dp_dev->hpd_status != HIBMC_HPD_IN)
+                       return connector_status_disconnected;
+       }
+
+       if (!hibmc_dp_get_dpcd(dp_dev))
+               return connector_status_disconnected;
+
+       if (!dp_dev->is_branch)
+               return connector_status_connected;
+
+       if (drm_dp_read_sink_count_cap(connector, dp_dev->dpcd, &dp_dev->desc) &&
+           dp_dev->downstream_ports[0] & DP_DS_PORT_HPD) {
+               ret = drm_dp_read_sink_count(dp_dev->aux);
+               if (ret > 0)
+                       return connector_status_connected;
+       }
 
-       return drm_connector_helper_detect_from_ddc(connector, ctx, force);
+       return connector_status_disconnected;
 }
 
 static const struct drm_connector_helper_funcs hibmc_dp_conn_helper_funcs = {
@@ -115,7 +157,7 @@ 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;
+       int idx, exp_status;
 
        if (!drm_dev_enter(dev, &idx))
                return -ENODEV;
@@ -123,12 +165,14 @@ irqreturn_t hibmc_dp_hpd_isr(int irq, void *arg)
        if (priv->dp.irq_status & DP_MASKED_SINK_HPD_PLUG_INT) {
                drm_dbg_dp(&priv->dev, "HPD IN isr occur!\n");
                hibmc_dp_hpd_cfg(&priv->dp);
+               exp_status = HIBMC_HPD_IN;
        } else {
                drm_dbg_dp(&priv->dev, "HPD OUT isr occur!\n");
                hibmc_dp_reset_link(&priv->dp);
+               exp_status = HIBMC_HPD_OUT;
        }
 
-       if (dev->registered)
+       if (hibmc_dp_check_hpd_status(&priv->dp, exp_status))
                drm_connector_helper_hpd_irq_event(&priv->dp.connector);
 
        drm_dev_exit(idx);