[PATCH 1/4] drm: try to restore previous CRTC config if mode set fails

[Alex Deucher]

On Mon, Nov 7, 2011 at 1:39 PM, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> We restore the CRTC, encoder, and connector configurations, but if the
> mode set failed, the attached display may have been turned off, so we
> need to try set_config again to restore things to the way they were.
>
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>

Reviewed-by: Alex Deucher <alexdeucher at gmail.com>

> ---
>  drivers/gpu/drm/drm_crtc_helper.c |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
> index f88a9b2..edaf903 100644
> --- a/drivers/gpu/drm/drm_crtc_helper.c
> +++ b/drivers/gpu/drm/drm_crtc_helper.c
> @@ -479,6 +479,7 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
>        struct drm_connector *save_connectors, *connector;
>        int count = 0, ro, fail = 0;
>        struct drm_crtc_helper_funcs *crtc_funcs;
> +       struct drm_mode_set save_set;
>        int ret = 0;
>        int i;
>
> @@ -551,6 +552,12 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
>                save_connectors[count++] = *connector;
>        }
>
> +       save_set.crtc = set->crtc;
> +       save_set.mode = &set->crtc->mode;
> +       save_set.x = set->crtc->x;
> +       save_set.y = set->crtc->y;
> +       save_set.fb = set->crtc->fb;
> +
>        /* We should be able to check here if the fb has the same properties
>         * and then just flip_or_move it */
>        if (set->crtc->fb != set->fb) {
> @@ -716,6 +723,12 @@ fail:
>                *connector = save_connectors[count++];
>        }
>
> +       /* Try to restore the config */
> +       if (mode_changed &&
> +           !drm_crtc_helper_set_mode(save_set.crtc, save_set.mode, save_set.x,
> +                                     save_set.y, save_set.fb))
> +               DRM_ERROR("failed to restore config after modeset failure\n");
> +
>        kfree(save_connectors);
>        kfree(save_encoders);
>        kfree(save_crtcs);
> --
> 1.7.4.1
>
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