On Fri, Oct 21, 2016 at 04:45:39PM -0700, Manasi Navare wrote:
> This function provides a way for the driver to redo a
> modeset on the current mode and retry the link training
> at a lower link rate/lane count/bpp. This will get called
> incase the link training fails during the current modeset.
>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_atomic_helper.c | 58 +++++++++++++++++++++++++++++++++++++
> include/drm/drm_atomic_helper.h | 1 +
> 2 files changed, 59 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index f936276..0c1614e 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -2895,6 +2895,64 @@ int drm_atomic_helper_connector_dpms(struct drm_connector *connector,
> EXPORT_SYMBOL(drm_atomic_helper_connector_dpms);
>
> /**
> + * drm_atomic_helper_connector_modeset - Force a modeset on a connector
> + * @connector: DRM connector
> + *
> + * Provides a way to redo a modeset with the current mode so that it can
> + * drop the bpp, link rate/lane count and retry the link training.
> + *
> + * Returns:
> + * Returns 0 on success, negative errno numbers on failure.
> + */
> +int
> +drm_atomic_helper_connector_modeset(struct drm_connector *connector)
> +{
> + struct drm_device *dev = connector->dev;
> + struct drm_modeset_acquire_ctx ctx;
> + struct drm_atomic_state *state;
> + struct drm_connector_state *connector_state;
> + struct drm_crtc_state *crtc_state;
> + int ret = 0;
> +
> + drm_modeset_acquire_init(&ctx, 0);
> + state = drm_atomic_state_alloc(dev);
> + if (!state) {
> + ret = -ENOMEM;
> + goto fail;
> + }
> + state->acquire_ctx = &ctx;
> +retry:
> + ret = 0;
> + connector_state = drm_atomic_get_connector_state(state, connector);
> + if (IS_ERR(connector_state)) {
> + ret = PTR_ERR(connector_state);
> + goto fail;
> + }
> + if (!connector_state->crtc)
> + goto fail;
> +
> + crtc_state = drm_atomic_get_existing_crtc_state(state,
> + connector_state->crtc);
> + crtc_state->connectors_changed = true;
This line here only works if the driver uses the helpers for checking and
commit, and when it doesn't overwrite connectors_changed. I think the
kerneldoc should mention this.
The other issue: You cannot call this from modeset code itself because of
recursion. I think this also must be mentioned.
-Daniel
> + ret = drm_atomic_commit(state);
> +fail:
> + if (ret == -EDEADLK) {
> + drm_atomic_state_clear(state);
> + drm_modeset_backoff(&ctx);
> + goto retry;
> + }
> +
> + if (state)
> + drm_atomic_state_put(state);
> +
> + drm_modeset_drop_locks(&ctx);
> + drm_modeset_acquire_fini(&ctx);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_connector_modeset);
> +
> +/**
> * drm_atomic_helper_best_encoder - Helper for &drm_connector_helper_funcs
> * ->best_encoder callback
> * @connector: Connector control structure
> diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> index 7ff92b0..8de24dc 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -126,6 +126,7 @@ int drm_atomic_helper_page_flip(struct drm_crtc *crtc,
> uint32_t flags);
> int drm_atomic_helper_connector_dpms(struct drm_connector *connector,
> int mode);
> +int drm_atomic_helper_connector_modeset(struct drm_connector *connector);
> struct drm_encoder *
> drm_atomic_helper_best_encoder(struct drm_connector *connector);
>
> --
> 1.9.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
