On Wed, Nov 01, 2017 at 04:04:33PM +0100, Maarten Lankhorst wrote:
> This introduces a slight behavioral change to rmfb. Instead of
> disabling a crtc when the primary plane is disabled, we try to
> preserve it.
>
> Apart from old versions of the vmwgfx xorg driver, there is
> nothing depending on rmfb disabling a crtc.
>
> Vmwgfx' and simple kms helper atomic implementation rejects CRTC
> enabled without plane, so we can do this safely.
>
> If the atomic commit is rejected by the driver then we will still
> fall back to the old behavior and turn off the crtc.
>
> Changes since v1:
> - Restart completely when rmfb with crtc on fails (Sean Paul).
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> ---
> drivers/gpu/drm/drm_framebuffer.c | 23 +++++++++++++++++------
> 1 file changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
> index 2affe53f3fda..f0679468f421 100644
> --- a/drivers/gpu/drm/drm_framebuffer.c
> +++ b/drivers/gpu/drm/drm_framebuffer.c
> @@ -765,14 +765,18 @@ static int atomic_remove_fb(struct drm_framebuffer *fb)
> struct drm_plane *plane;
> struct drm_connector *conn;
> struct drm_connector_state *conn_state;
> - int i, ret = 0;
> + int i, ret;
> unsigned plane_mask;
> + bool disable_crtcs = false;
>
> - state = drm_atomic_state_alloc(dev);
> - if (!state)
> - return -ENOMEM;
> -
> +retry_disable:
> drm_modeset_acquire_init(&ctx, 0);
> +
> + state = drm_atomic_state_alloc(dev);
> + if (!state) {
> + ret = -ENOMEM;
> + goto out;
> + }
> state->acquire_ctx = &ctx;
>
> retry:
> @@ -793,7 +797,7 @@ static int atomic_remove_fb(struct drm_framebuffer *fb)
> goto unlock;
> }
>
> - if (plane_state->crtc->primary == plane) {
> + if (disable_crtcs && plane_state->crtc->primary == plane) {
> struct drm_crtc_state *crtc_state;
>
> crtc_state = drm_atomic_get_existing_crtc_state(state, plane_state->crtc);
> @@ -818,6 +822,7 @@ static int atomic_remove_fb(struct drm_framebuffer *fb)
> plane->old_fb = plane->fb;
> }
>
> + /* This list is only filled when disable_crtcs is set. */
> for_each_new_connector_in_state(state, conn, conn_state, i) {
WARN_ON(!disable_crtcs) maybe?
> ret = drm_atomic_set_crtc_for_connector(conn_state, NULL);
>
> @@ -840,9 +845,15 @@ static int atomic_remove_fb(struct drm_framebuffer *fb)
>
> drm_atomic_state_put(state);
>
> +out:
> drm_modeset_drop_locks(&ctx);
> drm_modeset_acquire_fini(&ctx);
>
> + if (ret == -EINVAL && !disable_crtcs) {
Hmm. -EINVAL seems rather specific. Not sure if we could just check for
any error?
Or... I'm not sure if we have any central place where we do the
"can I disable the primary plane w/o disabling the crtc?" check. If we
do then we could also add a comment there informing people that the
-EINVAL is important.
> + disable_crtcs = true;
> + goto retry_disable;
> + }
> +
> return ret;
> }
>
> --
> 2.14.1
>
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--
Ville Syrjälä
Intel OTC
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