drm/i915/lobf: Add mutex for alpm update

The ALPM_CTL can be updated from different context, so
add mutex to sychonize the update.

Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://lore.kernel.org/r/20250423092334.2294483-9-animesh.manna@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c
index 269768c95a3dd8e17f184c89245f718162defcc2..606cb3e5f30d1d99e2ea4ae13dc1ad8f6cadbab9 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_alpm.c
+++ b/drivers/gpu/drm/i915/display/intel_alpm.c
@@ -25,7 +25,7 @@ bool intel_alpm_aux_less_wake_supported(struct intel_dp *intel_dp)
        return intel_dp->alpm_dpcd & DP_ALPM_AUX_LESS_CAP;
 }
 
-void intel_alpm_init_dpcd(struct intel_dp *intel_dp)
+void intel_alpm_init(struct intel_dp *intel_dp)
 {
        u8 dpcd;
 
@@ -33,6 +33,7 @@ void intel_alpm_init_dpcd(struct intel_dp *intel_dp)
                return;
 
        intel_dp->alpm_dpcd = dpcd;
+       mutex_init(&intel_dp->alpm_parameters.lock);
 }
 
 /*
@@ -331,6 +332,7 @@ static void lnl_alpm_configure(struct intel_dp *intel_dp,
            (!crtc_state->has_sel_update && !intel_dp_is_edp(intel_dp)))
                return;
 
+       mutex_lock(&intel_dp->alpm_parameters.lock);
        /*
         * Panel Replay on eDP is always using ALPM aux less. I.e. no need to
         * check panel support at this point.
@@ -372,6 +374,7 @@ static void lnl_alpm_configure(struct intel_dp *intel_dp,
        alpm_ctl |= ALPM_CTL_ALPM_ENTRY_CHECK(intel_dp->alpm_parameters.check_entry_lines);
 
        intel_de_write(display, ALPM_CTL(display, cpu_transcoder), alpm_ctl);
+       mutex_unlock(&intel_dp->alpm_parameters.lock);
 }
 
 void intel_alpm_configure(struct intel_dp *intel_dp,
@@ -411,8 +414,10 @@ void intel_alpm_pre_plane_update(struct intel_atomic_state *state,
                        continue;
 
                if (old_crtc_state->has_lobf) {
+                       mutex_lock(&intel_dp->alpm_parameters.lock);
                        intel_de_write(display, ALPM_CTL(display, cpu_transcoder), 0);
                        drm_dbg_kms(display->drm, "Link off between frames (LOBF) disabled\n");
+                       mutex_unlock(&intel_dp->alpm_parameters.lock);
                }
        }
 }
@@ -531,6 +536,8 @@ void intel_alpm_disable(struct intel_dp *intel_dp)
        if (DISPLAY_VER(display) < 20)
                return;
 
+       mutex_lock(&intel_dp->alpm_parameters.lock);
+
        intel_de_rmw(display, ALPM_CTL(display, cpu_transcoder),
                     ALPM_CTL_ALPM_ENABLE | ALPM_CTL_LOBF_ENABLE |
                     ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
@@ -538,4 +545,6 @@ void intel_alpm_disable(struct intel_dp *intel_dp)
        intel_de_rmw(display,
                     PORT_ALPM_CTL(cpu_transcoder),
                     PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
+
+       mutex_unlock(&intel_dp->alpm_parameters.lock);
 }

diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h b/drivers/gpu/drm/i915/display/intel_alpm.h
index 77bae022a0eafd865f153d63175334c0a88221a0..c043a071f84f3124a11f0f15a0d8d6990c0e9e17 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_alpm.h
+++ b/drivers/gpu/drm/i915/display/intel_alpm.h
@@ -15,7 +15,7 @@ struct intel_connector;
 struct intel_atomic_state;
 struct intel_crtc;
 
-void intel_alpm_init_dpcd(struct intel_dp *intel_dp);
+void intel_alpm_init(struct intel_dp *intel_dp);
 bool intel_alpm_compute_params(struct intel_dp *intel_dp,
                               const struct intel_crtc_state *crtc_state);
 void intel_alpm_lobf_compute_config(struct intel_dp *intel_dp,

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 457a2fb9efa8c7794a4d43cd44fc36d3b356263e..878f378577ab64e554bb728a7b3aa8bf44e8e201 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1809,6 +1809,7 @@ struct intel_dp {
                u8 io_wake_lines;
                u8 fast_wake_lines;
                enum transcoder transcoder;
+               struct mutex lock;
 
                /* LNL and beyond */
                u8 check_entry_lines;

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 660b1a8c39a46aaeeecaaf4f9cc7bbb61a278b0a..ece787bb3335750da7c14577209588ea48c91415 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -6391,7 +6391,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
         */
        intel_hpd_enable_detection(encoder);
 
-       intel_alpm_init_dpcd(intel_dp);
+       intel_alpm_init(intel_dp);
 
        /* Cache DPCD and EDID for edp. */
        has_dpcd = intel_edp_init_dpcd(intel_dp, connector);