On Wed, Dec 7, 2022 at 3:09 AM xurui <xurui@xxxxxxxxxx> wrote:
>
> HPD signals on DVI ports can be fired off before the pins required for
> DDC probing actually make contact, due to the pins for HPD making
> contact first. This results in a HPD signal being asserted but DDC
> probing failing, resulting in hotplugging occasionally failing.
It seems like DP should get a similar fix.
>
> Rescheduling the hotplug work for a second when we run into an HPD
> signal with a failing DDC probe usually gives enough time for the rest
> of the connector's pins to make contact, and fixes this issue.
This looks reasonable. Please address the kernel test robot reports.
Thanks,
Alex
>
> Signed-off-by: xurui <xurui@xxxxxxxxxx>
> ---
> .../gpu/drm/amd/amdgpu/amdgpu_connectors.c | 22 ++++++++++++++++++-
> drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h | 1 +
> 2 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> index cfb262911bfc..dd8d414249a5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> @@ -997,13 +997,33 @@ amdgpu_connector_dvi_detect(struct drm_connector *connector, bool force)
> }
> }
>
> + if (amdgpu_connector->detected_hpd_without_ddc) {
> + force = true;
> + amdgpu_connector->detected_hpd_without_ddc = false;
> + }
> +
> if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) {
> ret = connector->status;
> goto exit;
> }
>
> - if (amdgpu_connector->ddc_bus)
> + if (amdgpu_connector->ddc_bus) {
> dret = amdgpu_display_ddc_probe(amdgpu_connector, false);
> +
> + /* Sometimes the pins required for the DDC probe on DVI
> + * connectors don't make contact at the same time that the ones
> + * for HPD do. If the DDC probe fails even though we had an HPD
> + * signal, try again later
> + */
> + if (!dret && !force &&
> + amdgpu_display_hpd_sense(adev, amdgpu_connector->hpd.hpd)) {
> + DRM_DEBUG_KMS("hpd detected without ddc, retrying in 1 second\n");
> + amdgpu_connector->detected_hpd_without_ddc = true;
> + schedule_delayed_work(&adev->hotplug_work,
> + msecs_to_jiffies(1000));
> + goto exit;
> + }
> + }
> if (dret) {
> amdgpu_connector->detected_by_load = false;
> amdgpu_connector_free_edid(connector);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> index 37322550d750..bf009de59710 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> @@ -535,6 +535,7 @@ struct amdgpu_connector {
> void *con_priv;
> bool dac_load_detect;
> bool detected_by_load; /* if the connection status was determined by load */
> + bool detected_hpd_without_ddc; /* if an HPD signal was detected on DVI, but ddc probing failed */
> uint16_t connector_object_id;
> struct amdgpu_hpd hpd;
> struct amdgpu_router router;
> --
> 2.25.1
>
>
> No virus found
> Checked by Hillstone Network AntiVirus
