mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-28 18:05:00 -04:00
Code Issues Packages Projects Releases Wiki Activity

drm/i915/dp_link_training: Reset the max link limits in the fallback code

Browse Source 
The target maximum rate/lane count selected by the fallback logic may
exceed the current link_caps max_limits' rate/lane count, the latter of
which are used as a limit by the lookup functions when filtering allowed
configurations. To ensure the fallback search finds all relevant
candidates, temporarily reset the link_caps max_limits to the maximum
common supported capabilities.

After the fallback search completes, set the link_caps max_limits to the
configuration selected by the fallback logic, as before, determining
the allowed configurations for a subsequent modeset.

Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260701153204.4124150-24-imre.deak@intel.com
This commit is contained in:
Imre Deak
2026-07-01 18:31:52 +03:00
parent 77265110e0
commit 9cee806ef5
1 changed files with 34 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
drivers/gpu/drm/i915/display/intel_dp_link_training.c
View File

@@ -1960,10 +1960,12 @@ static bool reduce_link_params(struct intel_dp *intel_dp, const struct intel_crt
static int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
const struct intel_crtc_state *crtc_state)
{
struct intel_display *display = to_intel_display(intel_dp);
struct intel_dp_link_caps *link_caps = intel_dp->link.caps;
struct intel_dp_link_config max_link_limits;
int new_link_rate;
int new_lane_count;
int err = -1;
if (intel_dp_is_edp(intel_dp) && !intel_dp->use_max_params) {
lt_dbg(intel_dp, DP_PHY_DPRX,
@@ -1972,14 +1974,32 @@ static int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
return 0;
}
/*
* Temporarily reset the max link limit before selecting the fallback
* config.
*
* After fallback, the current logic narrows the allowed configurations
* to the selected config's rate and lane count. That can make a later
* fallback candidate fall outside the current max_limit, so reset it
* before searching.
*
* TODO: Constrain the allowed configurations by only disabling individual
* configurations and remove setting maximum link parameters.
*/
intel_dp_link_caps_get_max_limits(link_caps, &max_link_limits);
intel_dp_link_caps_reset_max_limits(link_caps);
if (!reduce_link_params(intel_dp, crtc_state, &new_link_rate, &new_lane_count))
return -1;
goto out_restore_max_limits;
if (intel_dp_is_edp(intel_dp) &&
!intel_dp_can_link_train_fallback_for_edp(intel_dp, new_link_rate, new_lane_count)) {
lt_dbg(intel_dp, DP_PHY_DPRX,
"Retrying Link training for eDP with same parameters\n");
return 0;
err = 0;
goto out_restore_max_limits;
}
lt_dbg(intel_dp, DP_PHY_DPRX,
@@ -1990,10 +2010,19 @@ static int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
max_link_limits.rate = new_link_rate;
max_link_limits.lane_count = new_lane_count;
/* TODO: handle an update failure */
intel_dp_link_caps_set_max_limits(link_caps, &max_link_limits);
err = 0;
return 0;
out_restore_max_limits:
/*
* Shouldn't fail: setting max_limits can only fail if they drop below
* the optionally forced rate/lane-count parameters, but the reduced
* config was chosen to satisfy those constraints.
*/
if (drm_WARN_ON(display->drm,
!intel_dp_link_caps_set_max_limits(link_caps, &max_link_limits)))
err = -1;
return err;
}
static bool intel_dp_schedule_fallback_link_training(struct intel_atomic_state *state,