Now, we check the presence of the EDID to determine if there is a monitor
present.

DVI-I connectors have both analog and digital encoders and the HPD pin
is only reliable on the digital part.

But when I pull out the Radeon HD8570's HDMI connector, the HDMI status
in system is still perform connected.

asd@asd-PC:~$ cat /sys/class/drm/card0-HDMI-A-1/status 
connected

At this moment, if I want to read the EDID by /dev/i2c-X with I2C
driver, there is no EDID can be read.

Dmesg witha drm.debug=0x6, we can find the following message:

[drm:drm_helper_hpd_irq_event] [CONNECTOR:41:HDMI-A-1] status
updated from connected to connected

Based on the appearance, I thought to check the HPD status again, because
the HPD status is perform disconnected, after amdgpu_display_ddc_probe().
If the amdgpu_display_hpd_sense() return false, I think the HDMI connector
status is undefined, and just return disconnected simply.

I'm not sure if it happened to other AMD cards.

Signed-off-by: Binbin Zhou <zhoubb.aa...@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
index f355d9a752d2..ee657db9a228 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -973,7 +973,7 @@ amdgpu_connector_dvi_detect(struct drm_connector 
*connector, bool force)
        const struct drm_encoder_helper_funcs *encoder_funcs;
        int r;
        enum drm_connector_status ret = connector_status_disconnected;
-       bool dret = false, broken_edid = false;
+       bool dret = false, broken_edid = false, undefined_flag = false;
 
        if (!drm_kms_helper_is_poll_worker()) {
                r = pm_runtime_get_sync(connector->dev->dev);
@@ -988,7 +988,12 @@ amdgpu_connector_dvi_detect(struct drm_connector 
*connector, bool force)
 
        if (amdgpu_connector->ddc_bus)
                dret = amdgpu_display_ddc_probe(amdgpu_connector, false);
-       if (dret) {
+
+       /* Check the HDMI HPD pin status again */
+       if (!amdgpu_display_hpd_sense(adev, amdgpu_connector->hpd.hpd))
+               undefined_flag = true;
+
+       if (dret && !undefined_flag) {
                amdgpu_connector->detected_by_load = false;
                amdgpu_connector_free_edid(connector);
                amdgpu_connector_get_edid(connector);
-- 
2.17.1

_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx

Reply via email to