On Sat, May 16, 2026 at 2:52 PM Gilles Risch <gilles.risch@gmail.com> wrote:
>
> After suspend/resume the internal eDP display on iMac11,1 (and
> potentially other DCE3.1 systems) stays dark because
> atombios_set_edp_panel_power() skips panel power control for
> anything older than DCE4.
>
> Fix this by:
> - Extending atombios_set_edp_panel_power() to also handle DCE3.1
>   by changing the !ASIC_IS_DCE4() guard to !ASIC_IS_DCE31().
>   HPD polling works correctly on DCE3.1 (verified: HPD is asserted
>   at iteration 0 on iMac11,1).
> - Issuing ATOM_ENCODER_CMD_DP_VIDEO_ON/OFF for DCE3.1 in addition
>   to DCE4+.
>
> Tested on iMac11,1 (Mobility Radeon HD 4850, RV770/DCE3.1).
>
> Signed-off-by: Gilles Risch <gilles.risch@gmail.com>
> ---
>  drivers/gpu/drm/radeon/atombios_encoders.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
> index 4e984973c043..b62fd713efcf 100644
> --- a/drivers/gpu/drm/radeon/atombios_encoders.c
> +++ b/drivers/gpu/drm/radeon/atombios_encoders.c
> @@ -1383,7 +1383,7 @@ atombios_set_edp_panel_power(struct drm_connector *connector, int action)
>         if (connector->connector_type != DRM_MODE_CONNECTOR_eDP)
>                 goto done;
>
> -       if (!ASIC_IS_DCE4(rdev))
> +       if (!ASIC_IS_DCE31(rdev))
>                 goto done;
>
>         if ((action != ATOM_TRANSMITTER_ACTION_POWER_ON) &&
> @@ -1707,7 +1707,7 @@ radeon_atom_encoder_dpms_dig(struct drm_encoder *encoder, int mode)
>                 if (ENCODER_MODE_IS_DP(atombios_get_encoder_mode(encoder)) && connector) {
>                         /* DP_SET_POWER_D0 is set in radeon_dp_link_train */
>                         radeon_dp_link_train(encoder, connector);
> -                       if (ASIC_IS_DCE4(rdev))
> +                       if (ASIC_IS_DCE4(rdev) || ASIC_IS_DCE31(rdev))
>                                 atombios_dig_encoder_setup(encoder, ATOM_ENCODER_CMD_DP_VIDEO_ON, 0);
>                 }
>                 if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT)) {
> @@ -1724,7 +1724,7 @@ radeon_atom_encoder_dpms_dig(struct drm_encoder *encoder, int mode)
>         case DRM_MODE_DPMS_SUSPEND:
>         case DRM_MODE_DPMS_OFF:
>
> -               if (ASIC_IS_DCE4(rdev)) {
> +               if (ASIC_IS_DCE4(rdev) || ASIC_IS_DCE31(rdev)) {
>                         if (ENCODER_MODE_IS_DP(atombios_get_encoder_mode(encoder)) && connector)
>                                 atombios_dig_encoder_setup(encoder, ATOM_ENCODER_CMD_DP_VIDEO_OFF, 0);
>                 }

These changes don't make sense and will break other DCE3.c boards.   I
had the attached patch from you in one of my old branches, does it fix
the issue?

Alex