Commit 99e43c54 authored by Lyude Paul's avatar Lyude Paul Committed by Greg Kroah-Hartman
Browse files

drm/i915: Skip vcpi allocation for MSTB ports that are gone

commit c02ba4ef


Since we need to be able to allow DPMS on->off prop changes after an MST
port has disappeared from the system, we need to be able to make sure we
can compute a config for the resulting atomic commit. Currently this is
impossible when the port has disappeared, since the VCPI slot searching
we try to do in intel_dp_mst_compute_config() will fail with -EINVAL.

Since the only commits we want to allow on no-longer-present MST ports
are ones that shut off display hardware, we already know that no VCPI
allocations are needed. So, hardcode the VCPI slot count to 0 when
intel_dp_mst_compute_config() is called on an MST port that's gone.

Changes since V4:
- Don't use mst_port_gone at all, just check whether or not the drm
  connector is registered - Daniel Vetter

Signed-off-by: default avatarLyude Paul <>
Reviewed-by: default avatarDaniel Vetter <>
(cherry picked from commit f67207d7

Signed-off-by: default avatarRodrigo Vivi <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 9ab995db
......@@ -37,11 +37,11 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
struct intel_digital_port *intel_dig_port = intel_mst->primary;
struct intel_dp *intel_dp = &intel_dig_port->dp;
struct intel_connector *connector =
struct drm_connector *connector = conn_state->connector;
void *port = to_intel_connector(connector)->port;
struct drm_atomic_state *state = pipe_config->base.state;
int bpp;
int lane_count, slots;
int lane_count, slots = 0;
const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
int mst_pbn;
bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc,
......@@ -66,17 +66,23 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
pipe_config->port_clock = intel_dp_max_link_rate(intel_dp);
if (drm_dp_mst_port_has_audio(&intel_dp->mst_mgr, connector->port))
if (drm_dp_mst_port_has_audio(&intel_dp->mst_mgr, port))
pipe_config->has_audio = true;
mst_pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock, bpp);
pipe_config->pbn = mst_pbn;
slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp->mst_mgr,
connector->port, mst_pbn);
if (slots < 0) {
DRM_DEBUG_KMS("failed finding vcpi slots:%d\n", slots);
return false;
/* Zombie connectors can't have VCPI slots */
if (READ_ONCE(connector->registered)) {
slots = drm_dp_atomic_find_vcpi_slots(state,
if (slots < 0) {
DRM_DEBUG_KMS("failed finding vcpi slots:%d\n",
return false;
intel_link_compute_m_n(bpp, lane_count,
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