From: Baihan Li <libaihan@huawei.com>

If the system started with VGA connected, the desktop like GDM cannot get
DP's CRTC when DP device is plugged in, because there is only one crtc
sharing use of VGA and DP. So change VGA to disconnected when DP is
connected.

Fixes: 4c962bc929f1 ("drm/hisilicon/hibmc: Add vga connector detect functions")
Signed-off-by: Baihan Li <libaihan@huawei.com>
---
 drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
index 36401b46034c..73dd3d5fc26c 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
@@ -49,6 +49,18 @@ static int hibmc_connector_get_modes(struct drm_connector *connector)
 	return count;
 }
 
+static int hibmc_vdac_detect(struct drm_connector *connector, struct drm_modeset_acquire_ctx *ctx,
+			     bool force)
+{
+	struct hibmc_drm_private *priv = to_hibmc_drm_private(connector->dev);
+	struct hibmc_dp *dp = &priv->dp;
+
+	if (dp->hpd_status)
+		return connector_status_disconnected;
+
+	return connector_status_connected;
+}
+
 static void hibmc_connector_destroy(struct drm_connector *connector)
 {
 	struct hibmc_vdac *vdac = to_hibmc_vdac(connector);
@@ -60,7 +72,7 @@ static void hibmc_connector_destroy(struct drm_connector *connector)
 static const struct drm_connector_helper_funcs
 	hibmc_connector_helper_funcs = {
 	.get_modes = hibmc_connector_get_modes,
-	.detect_ctx = drm_connector_helper_detect_from_ddc,
+	.detect_ctx = hibmc_vdac_detect,
 };
 
 static const struct drm_connector_funcs hibmc_connector_funcs = {
-- 
2.33.0

On Fri, May 30, 2025 at 05:54:30PM +0800, Yongbang Shi wrote:
> From: Baihan Li <libaihan@huawei.com>
> 
> If the system started with VGA connected, the desktop like GDM cannot get
> DP's CRTC when DP device is plugged in, because there is only one crtc
> sharing use of VGA and DP. So change VGA to disconnected when DP is
> connected.

NAK. I think we discussed this when the previous patch was submitted.

VGA and DP are independent. It should be user's choice whether to use
VGA or DP if both are connected.

> 
> Fixes: 4c962bc929f1 ("drm/hisilicon/hibmc: Add vga connector detect functions")
> Signed-off-by: Baihan Li <libaihan@huawei.com>
> ---
>  drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)

-- 
With best wishes
Dmitry

> On Fri, May 30, 2025 at 05:54:30PM +0800, Yongbang Shi wrote:
>> From: Baihan Li <libaihan@huawei.com>
>>
>> If the system started with VGA connected, the desktop like GDM cannot get
>> DP's CRTC when DP device is plugged in, because there is only one crtc
>> sharing use of VGA and DP. So change VGA to disconnected when DP is
>> connected.
> NAK. I think we discussed this when the previous patch was submitted.
>
> VGA and DP are independent. It should be user's choice whether to use
> VGA or DP if both are connected.

Acutally, although we are developing drm drivers, our requirements
and testing department's goal is to displaying desktop systems(like GDM), so we have to
solve different OS or display managers problems, and let the driver handle more situations.


>> Fixes: 4c962bc929f1 ("drm/hisilicon/hibmc: Add vga connector detect functions")
>> Signed-off-by: Baihan Li <libaihan@huawei.com>
>> ---
>>   drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c | 14 +++++++++++++-
>>   1 file changed, 13 insertions(+), 1 deletion(-)

> On Fri, May 30, 2025 at 05:54:30PM +0800, Yongbang Shi wrote:
>> From: Baihan Li <libaihan@huawei.com>
>>
>> If the system started with VGA connected, the desktop like GDM cannot get
>> DP's CRTC when DP device is plugged in, because there is only one crtc
>> sharing use of VGA and DP. So change VGA to disconnected when DP is
>> connected.
> NAK. I think we discussed this when the previous patch was submitted.
>
> VGA and DP are independent. It should be user's choice whether to use
> VGA or DP if both are connected.

Okay, I can use GDM to set which connectors to use, or config Xorg conf file.
But I have an another problem, I think our driver only support one of them displaying, can we realize
the clone displaying at the same time? To make DP and VGA shows up simultaneous when DP is plugged in,
If the system started with VGA connected.

Thanks,
Baihan.


>> Fixes: 4c962bc929f1 ("drm/hisilicon/hibmc: Add vga connector detect functions")
>> Signed-off-by: Baihan Li <libaihan@huawei.com>
>> ---
>>   drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c | 14 +++++++++++++-
>>   1 file changed, 13 insertions(+), 1 deletion(-)