lgtm!
Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
On Fri, 2022-08-05 at 17:13 -0400, Hamza Mahfooz wrote:
> Currently, there is no way to identify if DSC pass-through can be
> enabled and what aux DSC pass-through requests ought to be sent to. So,
> add a variable to struct drm_dp_mst_port that keeps track of the
> aforementioned information.
>
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
> ---
> v2: define DP_DSC_PASSTHROUGH_IS_SUPPORTED
> ---
> drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
> include/drm/display/drm_dp.h | 1 +
> include/drm/display/drm_dp_mst_helper.h | 3 +++
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> index 67b3b9697da7..71915afd9892 100644
> --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> @@ -5921,8 +5921,10 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
> /* Enpoint decompression with DP-to-DP peer device */
> if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
> (endpoint_fec & DP_FEC_CAPABLE) &&
> - (upstream_dsc & 0x2) /* DSC passthrough */)
> + (upstream_dsc & DP_DSC_PASSTHROUGH_IS_SUPPORTED)) {
> + port->passthrough_aux = &immediate_upstream_port->aux;
> return &port->aux;
> + }
>
> /* Virtual DPCD decompression with DP-to-DP peer device */
> return &immediate_upstream_port->aux;
> diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
> index 9e3aff7e68bb..4d0abe4c7ea9 100644
> --- a/include/drm/display/drm_dp.h
> +++ b/include/drm/display/drm_dp.h
> @@ -239,6 +239,7 @@
>
> #define DP_DSC_SUPPORT 0x060 /* DP 1.4 */
> # define DP_DSC_DECOMPRESSION_IS_SUPPORTED (1 << 0)
> +# define DP_DSC_PASSTHROUGH_IS_SUPPORTED (1 << 1)
>
> #define DP_DSC_REV 0x061
> # define DP_DSC_MAJOR_MASK (0xf << 0)
> diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
> index 10adec068b7f..4a39c95f8afd 100644
> --- a/include/drm/display/drm_dp_mst_helper.h
> +++ b/include/drm/display/drm_dp_mst_helper.h
> @@ -86,6 +86,8 @@ struct drm_dp_vcpi {
> * @next: link to next port on this branch device
> * @aux: i2c aux transport to talk to device connected to this port, protected
> * by &drm_dp_mst_topology_mgr.base.lock.
> + * @passthrough_aux: parent aux to which DSC pass-through requests should be
> + * sent, only set if DSC pass-through is possible.
> * @parent: branch device parent of this port
> * @vcpi: Virtual Channel Payload info for this port.
> * @connector: DRM connector this port is connected to. Protected by
> @@ -140,6 +142,7 @@ struct drm_dp_mst_port {
> */
> struct drm_dp_mst_branch *mstb;
> struct drm_dp_aux aux; /* i2c bus for this port? */
> + struct drm_dp_aux *passthrough_aux;
> struct drm_dp_mst_branch *parent;
>
> struct drm_dp_vcpi vcpi;
--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat
