On Fri, Mar 9, 2018 at 12:27 PM, Michel Dänzer <mic...@daenzer.net> wrote:
> From: Michel Dänzer <michel.daen...@amd.com>
>
> Turning off the sink in this case causes various issues, because
> userspace expects it to stay on until it turns it off explicitly.
>
> Instead, turn the sink off and back on when a display is connected
> again. This dance seems necessary for link training to work correctly.
>
> Bugzilla: https://bugs.freedesktop.org/105308
> Signed-off-by: Michel Dänzer <michel.daen...@amd.com>
Reviewed-by: Alex Deucher <alexander.deuc...@amd.com>
Care to send a similar patch for radeon as well?
Alex
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 31
> ++++++++++----------------
> 1 file changed, 12 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> index ffc1f6f46913..9da8d5802980 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> @@ -69,25 +69,18 @@ void amdgpu_connector_hotplug(struct drm_connector
> *connector)
> /* don't do anything if sink is not display port, i.e.,
> * passive dp->(dvi|hdmi) adaptor
> */
> - if (dig_connector->dp_sink_type ==
> CONNECTOR_OBJECT_ID_DISPLAYPORT) {
> - int saved_dpms = connector->dpms;
> - /* Only turn off the display if it's physically
> disconnected */
> - if (!amdgpu_display_hpd_sense(adev,
> amdgpu_connector->hpd.hpd)) {
> - drm_helper_connector_dpms(connector,
> DRM_MODE_DPMS_OFF);
> - } else if
> (amdgpu_atombios_dp_needs_link_train(amdgpu_connector)) {
> - /* Don't try to start link training before we
> - * have the dpcd */
> - if
> (amdgpu_atombios_dp_get_dpcd(amdgpu_connector))
> - return;
> -
> - /* set it to OFF so that
> drm_helper_connector_dpms()
> - * won't return immediately since the current
> state
> - * is ON at this point.
> - */
> - connector->dpms = DRM_MODE_DPMS_OFF;
> - drm_helper_connector_dpms(connector,
> DRM_MODE_DPMS_ON);
> - }
> - connector->dpms = saved_dpms;
> + if (dig_connector->dp_sink_type ==
> CONNECTOR_OBJECT_ID_DISPLAYPORT &&
> + amdgpu_display_hpd_sense(adev, amdgpu_connector->hpd.hpd)
> &&
> + amdgpu_atombios_dp_needs_link_train(amdgpu_connector)) {
> + /* Don't start link training before we have the DPCD
> */
> + if (amdgpu_atombios_dp_get_dpcd(amdgpu_connector))
> + return;
> +
> + /* Turn the connector off and back on immediately,
> which
> + * will trigger link training
> + */
> + drm_helper_connector_dpms(connector,
> DRM_MODE_DPMS_OFF);
> + drm_helper_connector_dpms(connector,
> DRM_MODE_DPMS_ON);
> }
> }
> }
> --
> 2.16.2
>
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