Re: [PATCH] DRM/Radeon: On DVI-I use Load Detection when EDID is bogus.

[Alex Deucher <alexdeucher@gmail.com>]

On Wed, Oct 24, 2012 at 12:32 PM, Egbert Eich <eich@suse.de> wrote:
> The Radeon driver uses the analog/digital flag to determine if the
> DAC or the TMDS encoder should be enabled on a DVI-I connector.
> If the EDID is bogus this flag is no longer reliable. This fix
> adds a fallback to DAC load detection to determine if anything
> is connected to the DAC. If not and a (bogus) EDID is found it
> assumes a digital display is connected.
> This works around problems with some crappy IPMI devices using
> Radeon ES1000.

Looks good.  Added to by -fixes queue.

Thanks!

Alex

>
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/radeon/radeon_connectors.c |   28 +++++++++++++++++++++-------
>  1 files changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
> index 67cfc17..b884c36 100644
> --- a/drivers/gpu/drm/radeon/radeon_connectors.c
> +++ b/drivers/gpu/drm/radeon/radeon_connectors.c
> @@ -941,7 +941,7 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
>         struct drm_mode_object *obj;
>         int i;
>         enum drm_connector_status ret = connector_status_disconnected;
> -       bool dret = false;
> +       bool dret = false, broken_edid = false;
>
>         if (!force && radeon_check_hpd_status_unchanged(connector))
>                 return connector->status;
> @@ -965,6 +965,9 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
>                                 ret = connector_status_disconnected;
>                                 DRM_ERROR("%s: detected RS690 floating bus bug, stopping ddc detect\n", drm_get_connector_name(connector));
>                                 radeon_connector->ddc_bus = NULL;
> +                       } else {
> +                               ret = connector_status_connected;
> +                               broken_edid = true; /* defer use_digital to later */
>                         }
>                 } else {
>                         radeon_connector->use_digital = !!(radeon_connector->edid->input & DRM_EDID_INPUT_DIGITAL);
> @@ -1047,13 +1050,24 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
>
>                         encoder_funcs = encoder->helper_private;
>                         if (encoder_funcs->detect) {
> -                               if (ret != connector_status_connected) {
> -                                       ret = encoder_funcs->detect(encoder, connector);
> -                                       if (ret == connector_status_connected) {
> -                                               radeon_connector->use_digital = false;
> +                               if (!broken_edid) {
> +                                       if (ret != connector_status_connected) {
> +                                               /* deal with analog monitors without DDC */
> +                                               ret = encoder_funcs->detect(encoder, connector);
> +                                               if (ret == connector_status_connected) {
> +                                                       radeon_connector->use_digital = false;
> +                                               }
> +                                               if (ret != connector_status_disconnected)
> +                                                       radeon_connector->detected_by_load = true;
>                                         }
> -                                       if (ret != connector_status_disconnected)
> -                                               radeon_connector->detected_by_load = true;
> +                               } else {
> +                                       enum drm_connector_status lret;
> +                                       /* assume digital unless load detected otherwise */
> +                                       radeon_connector->use_digital = true;
> +                                       lret = encoder_funcs->detect(encoder, connector);
> +                                       DRM_DEBUG_KMS("load_detect %x returned: %x\n",encoder->encoder_type,lret);
> +                                       if (lret == connector_status_connected)
> +                                               radeon_connector->use_digital = false;
>                                 }
>                                 break;
>                         }
> --
> 1.7.6.3
>