From 7c70884cd2b1b83bc904aacf0fd5caeee62f0b90 Mon Sep 17 00:00:00 2001 From: "Chia-Lin Kao (AceLan)" Date: Mon, 2 Mar 2026 13:11:47 +0800 Subject: [PATCH 2/2] debug Signed-off-by: Chia-Lin Kao (AceLan) --- .../drm/i915/display/intel_display_types.h | 1 + drivers/gpu/drm/i915/display/intel_dp.c | 34 +++++++++++++++++-- drivers/usb/typec/class.c | 15 ++++++-- drivers/usb/typec/ucsi/displayport.c | 18 ++++++++++ drivers/usb/typec/ucsi/ucsi.c | 7 ++++ 5 files changed, 71 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h index 2b2abbc839130..8f6c507aab436 100644 --- a/drivers/gpu/drm/i915/display/intel_display_types.h +++ b/drivers/gpu/drm/i915/display/intel_display_types.h @@ -1774,6 +1774,7 @@ struct intel_dp { bool is_mst; enum drm_dp_mst_mode mst_detect; + ktime_t last_short_hpd_time; /* debug: track rapid short HPD events */ /* connector directly attached - won't be use for modeset in mst world */ struct intel_connector *attached_connector; diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 8e62456398899..a539606134fd4 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -5113,6 +5113,7 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp) struct intel_encoder *encoder = &dig_port->base; bool link_ok = true; bool reprobe_needed = false; + int loop_count = 0; for (;;) { u8 esi[4] = {}; @@ -5126,7 +5127,16 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp) break; } - drm_dbg_kms(display->drm, "DPRX ESI: %4ph\n", esi); + drm_dbg_kms(display->drm, "DPRX ESI: %4ph (loop=%d active_streams=%d)\n", + esi, loop_count, intel_dp_mst_active_streams(intel_dp)); + loop_count++; + + if (loop_count > 8) { + drm_warn(display->drm, + "[ENCODER:%d:%s] MST ESI loop exceeded 8 iterations, breaking (ESI=%4ph)\n", + encoder->base.base.id, encoder->base.name, esi); + break; + } if (intel_dp_mst_active_streams(intel_dp) > 0 && link_ok && esi[3] & LINK_STATUS_CHANGED) { @@ -5144,8 +5154,12 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp) ack[3] |= DP_TUNNELING_IRQ; } - if (mem_is_zero(ack, sizeof(ack))) + if (mem_is_zero(ack, sizeof(ack))) { + drm_dbg_kms(display->drm, + "[ENCODER:%d:%s] MST ESI: no pending IRQs after %d iterations\n", + encoder->base.base.id, encoder->base.name, loop_count); break; + } if (!intel_dp_ack_sink_irq_esi(intel_dp, ack)) drm_dbg_kms(display->drm, "Failed to ack ESI\n"); @@ -6351,6 +6365,22 @@ intel_dp_hpd_pulse(struct intel_digital_port *dig_port, bool long_hpd) dig_port->base.base.name, long_hpd ? "long" : "short"); + if (!long_hpd && intel_dp->is_mst) { + ktime_t now = ktime_get(); + s64 delta_ms = ktime_ms_delta(now, intel_dp->last_short_hpd_time); + + drm_dbg_kms(display->drm, + "[ENCODER:%d:%s] MST short HPD: delta since last=%lldms\n", + dig_port->base.base.base.id, + dig_port->base.base.name, delta_ms); + if (delta_ms < 100) + drm_warn(display->drm, + "[ENCODER:%d:%s] MST rapid HPD detected: %lldms since last pulse\n", + dig_port->base.base.base.id, + dig_port->base.base.name, delta_ms); + intel_dp->last_short_hpd_time = now; + } + /* * TBT DP tunnels require the GFX driver to read out the DPRX caps in * response to long HPD pulses. The DP hotplug handler does that, diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c index 67a533e351506..280ab56ecbc46 100644 --- a/drivers/usb/typec/class.c +++ b/drivers/usb/typec/class.c @@ -305,10 +305,21 @@ void typec_altmode_update_active(struct typec_altmode *adev, bool active) return; if (!is_typec_port(adev->dev.parent) && adev->dev.driver) { - if (!active) + if (!active) { + dev_dbg(&adev->dev, + "DEBUG: altmode %s deactivated, dropping module ref (driver=%s)\n", + dev_name(&adev->dev), adev->dev.driver->name); module_put(adev->dev.driver->owner); - else + } else { + dev_dbg(&adev->dev, + "DEBUG: altmode %s activating, acquiring module ref (driver=%s)\n", + dev_name(&adev->dev), adev->dev.driver->name); WARN_ON(!try_module_get(adev->dev.driver->owner)); + } + } else if (!is_typec_port(adev->dev.parent) && !adev->dev.driver) { + dev_warn(&adev->dev, + "DEBUG: altmode %s has no driver bound, skipping module ref (active=%d)\n", + dev_name(&adev->dev), active); } adev->active = active; diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c index 8aae80b457d74..7079ec1996d62 100644 --- a/drivers/usb/typec/ucsi/displayport.c +++ b/drivers/usb/typec/ucsi/displayport.c @@ -54,6 +54,9 @@ static int ucsi_displayport_enter(struct typec_altmode *alt, u32 *vdo) u8 cur = 0; int ret; + dev_dbg(&alt->dev, "DEBUG: con%d ucsi_displayport_enter (initialized=%d override=%d)\n", + dp->con->num, dp->initialized, dp->override); + if (!ucsi_con_mutex_lock(dp->con)) return -ENOTCONN; @@ -113,6 +116,9 @@ static int ucsi_displayport_exit(struct typec_altmode *alt) u64 command; int ret = 0; + dev_dbg(&alt->dev, "DEBUG: con%d ucsi_displayport_exit (initialized=%d override=%d)\n", + dp->con->num, dp->initialized, dp->override); + if (!ucsi_con_mutex_lock(dp->con)) return -ENOTCONN; @@ -278,6 +284,10 @@ static void ucsi_displayport_work(struct work_struct *work) struct ucsi_dp *dp = container_of(work, struct ucsi_dp, work); int ret; + dev_dbg(&dp->alt->dev, + "DEBUG: con%d ucsi_displayport_work dispatching VDM header=0x%08x vdo_size=%d\n", + dp->con->num, dp->header, dp->vdo_size); + ret = typec_altmode_vdm(dp->alt, dp->header, dp->vdo_data, dp->vdo_size); if (ret) @@ -299,8 +309,16 @@ void ucsi_displayport_remove_partner(struct typec_altmode *alt) if (!dp) return; + dev_dbg(&alt->dev, + "DEBUG: con%d ucsi_displayport_remove_partner enter (initialized=%d) - waiting for work\n", + dp->con->num, dp->initialized); + cancel_work_sync(&dp->work); + dev_dbg(&alt->dev, + "DEBUG: con%d ucsi_displayport_remove_partner work done, clearing state\n", + dp->con->num); + dp->data.conf = 0; dp->data.status = 0; dp->initialized = false; diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c index 2104af0e3af1e..044f1486b904b 100644 --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -861,6 +861,10 @@ static int ucsi_check_altmodes(struct ucsi_connector *con) { int ret, num_partner_am; + dev_dbg(con->ucsi->dev, + "DEBUG: con%d ucsi_check_altmodes enter (partner=%p partner_altmode[0]=%p)\n", + con->num, con->partner, con->partner_altmode[0]); + ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP); if (ret && ret != -ETIMEDOUT) dev_err(con->ucsi->dev, @@ -871,6 +875,9 @@ static int ucsi_check_altmodes(struct ucsi_connector *con) if (con->partner_altmode[0]) { num_partner_am = ucsi_get_num_altmode(con->partner_altmode); typec_partner_set_num_altmodes(con->partner, num_partner_am); + dev_dbg(con->ucsi->dev, + "DEBUG: con%d calling ucsi_altmode_update_active (num_altmodes=%d)\n", + con->num, num_partner_am); ucsi_altmode_update_active(con); return 0; } else { -- 2.51.0