Reviewed-by: Karol Herbst <kherbst@xxxxxxxxxx>
On Fri, Sep 14, 2018 at 10:44 PM, Lyude Paul <lyude@xxxxxxxxxx> wrote:
> While we currently grab a runtime PM ref in nouveau's normal connector
> detection code, we apparently don't do this for MST. This means if we're
> in a scenario where the GPU is suspended and userspace attempts to do a
> connector probe on an MSTC connector, the probe will fail entirely due
> to the DP aux channel and GPU not being woken up:
>
> [ 316.633489] nouveau 0000:01:00.0: i2c: aux 000a: begin idle timeout ffffffff
> [ 316.635713] nouveau 0000:01:00.0: i2c: aux 000a: begin idle timeout ffffffff
> [ 316.637785] nouveau 0000:01:00.0: i2c: aux 000a: begin idle timeout ffffffff
> ...
>
> So, grab a runtime PM ref here.
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> drivers/gpu/drm/nouveau/dispnv50/disp.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> index c94b7f42d62d..9da0bdfe1e1c 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> @@ -938,9 +938,22 @@ static enum drm_connector_status
> nv50_mstc_detect(struct drm_connector *connector, bool force)
> {
> struct nv50_mstc *mstc = nv50_mstc(connector);
> + enum drm_connector_status conn_status;
> + int ret;
> +
> if (!mstc->port)
> return connector_status_disconnected;
> - return drm_dp_mst_detect_port(connector, mstc->port->mgr, mstc->port);
> +
> + ret = pm_runtime_get_sync(connector->dev->dev);
> + if (ret < 0 && ret != -EACCES)
> + return connector_status_disconnected;
> +
> + conn_status = drm_dp_mst_detect_port(connector, mstc->port->mgr,
> + mstc->port);
> +
> + pm_runtime_mark_last_busy(connector->dev->dev);
> + pm_runtime_put_autosuspend(connector->dev->dev);
> + return conn_status;
> }
>
> static void
> --
> 2.17.1
>
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