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drm/i915/dp_link_training: Track link recovery state with an enum

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Replace the sequential link training failure counter with an explicit
link recovery state enum.

This makes the recovery states and transitions clearer: idle, automatic
retraining pending, and automatic retraining disabled.

A follow-up change will also move the retrain_disabled flag into this
enum.

v2: (Jani)
- Convert enum intel_dp_link_recovery_state's documentation to be a
  non kernel-doc comment.
- Compare against / set enum values explicitly.

Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260601093836.3057345-16-imre.deak@intel.com
This commit is contained in:
Imre Deak
2026-06-01 12:38:28 +03:00
parent 1536edeee0
commit 4ba52dc9b4
1 changed files with 62 additions and 9 deletions
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71
drivers/gpu/drm/i915/display/intel_dp_link_training.c
View File

@@ -62,14 +62,54 @@
lt_dbg(_intel_dp, _dp_phy, "Sink disconnected: " _format, ## __VA_ARGS__); \
} while (0)
#define MAX_SEQ_TRAIN_FAILURES 2
/*
* enum intel_dp_link_recovery_state - LT recovery state
* @INTEL_DP_LINK_RECOVERY_IDLE:
* No link training failure is currently tracked and no recovery is
* in progress. This is the initial state after driver initialization,
* power state transitions, sink (re-)connection, or after a successful
* link training.
*
* @INTEL_DP_LINK_RECOVERY_AUTORETRAIN_PENDING:
* A first link training failure has been observed and an automatic
* retraining attempt with the same link parameters is pending. Exactly
* one such attempt is allowed before switching to userspace-driven
* recovery.
*
* @INTEL_DP_LINK_RECOVERY_AUTORETRAIN_DISABLED:
* Automatic retraining is no longer possible. At this point, a
* fallback selection is made and userspace is notified to take over
* recovery, performing modesets with parameters it determines are
* required. The driver then selects a link configuration from the
* remaining fallback configuration set. Subsequent link training
* failures trigger further fallback selections and userspace
* notifications.
*
* Describes the link recovery state used by the Intel DP link recovery
* logic.
*
* See also:
* - link_recovery_autoretrain_pending()
* - link_recovery_autoretrain_allowed()
* - link_recovery_mark_train_failure()
* - link_recovery_reset()
*/
enum intel_dp_link_recovery_state {
/*
* Keep the enum values ordered from least to most severe
* recovery state; helper logic relies on that ordering.
*/
INTEL_DP_LINK_RECOVERY_IDLE,
INTEL_DP_LINK_RECOVERY_AUTORETRAIN_PENDING,
INTEL_DP_LINK_RECOVERY_AUTORETRAIN_DISABLED,
};
struct intel_dp_link_training {
struct intel_dp *dp;
enum intel_dp_link_recovery_state recovery_state;
bool retrain_disabled;
/* Sequential link training failures after a passing LT */
int seq_train_failures;
int force_train_failure;
bool force_retrain;
};
@@ -1267,7 +1307,7 @@ intel_dp_128b132b_intra_hop(struct intel_dp *intel_dp,
static bool
link_recovery_autoretrain_pending(struct intel_dp_link_training *link_training)
{
return link_training->seq_train_failures == 1;
return link_training->recovery_state == INTEL_DP_LINK_RECOVERY_AUTORETRAIN_PENDING;
}
/*
@@ -1289,7 +1329,13 @@ link_recovery_autoretrain_pending(struct intel_dp_link_training *link_training)
static bool
link_recovery_autoretrain_allowed(struct intel_dp_link_training *link_training)
{
return link_training->seq_train_failures < MAX_SEQ_TRAIN_FAILURES;
switch (link_training->recovery_state) {
case INTEL_DP_LINK_RECOVERY_IDLE:
case INTEL_DP_LINK_RECOVERY_AUTORETRAIN_PENDING:
return true;
default:
return false;
}
}
/*
@@ -1307,9 +1353,16 @@ link_recovery_autoretrain_allowed(struct intel_dp_link_training *link_training)
static bool
link_recovery_mark_train_failure(struct intel_dp_link_training *link_training)
{
if (link_recovery_autoretrain_allowed(link_training))
/* Move to autoretrain pending or autoretrain disabled state. */
link_training->seq_train_failures++;
switch (link_training->recovery_state) {
case INTEL_DP_LINK_RECOVERY_IDLE:
link_training->recovery_state = INTEL_DP_LINK_RECOVERY_AUTORETRAIN_PENDING;
break;
case INTEL_DP_LINK_RECOVERY_AUTORETRAIN_PENDING:
link_training->recovery_state = INTEL_DP_LINK_RECOVERY_AUTORETRAIN_DISABLED;
break;
default:
break;
}
return link_recovery_autoretrain_allowed(link_training);
}
@@ -1323,7 +1376,7 @@ link_recovery_mark_train_failure(struct intel_dp_link_training *link_training)
*/
static void link_recovery_reset(struct intel_dp_link_training *link_training)
{
link_training->seq_train_failures = 0;
link_training->recovery_state = INTEL_DP_LINK_RECOVERY_IDLE;
}
/**