[PATCH v2 10/13] drm/i915/display: Enable DC3CO idle protocol in ALPM

Dibin Moolakadan Subrahmanian
2026-04-22T16:26:27Z

Add PR_ALPM_CTL_USE_DC3CO_IDLE_PROTOCOL bit definition and set it
when DC3CO is allowed.

Changes in v2:
- Squash "Define DC3CO idle protocol bit in PR_ALPM_CTL"
into this patch (Uma Shankar)
- Use intel_display_power_dc3co_allowed(display)
instead of intel_dc3co_allowed(state)

BSpec: 75253
Signed-off-by: Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian@intel.com>
---
drivers/gpu/drm/i915/display/intel_alpm.c | 6 ++++++
drivers/gpu/drm/i915/display/intel_psr_regs.h | 1 +
2 files changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c
index a7350ce8e716..6394d1568b54 100644
--- a/drivers/gpu/drm/i915/display/intel_alpm.c
+++ b/drivers/gpu/drm/i915/display/intel_alpm.c
@@ -389,6 +389,12 @@ static void lnl_alpm_configure(struct intel_dp *intel_dp,
if (crtc_state->disable_as_sdp_when_pr_active)
pr_alpm_ctl |= PR_ALPM_CTL_AS_SDP_TRANSMISSION_IN_ACTIVE_DISABLE;

+ if (intel_display_power_dc3co_allowed(display) &&
+ intel_display_power_dc3co_supported(display))
+ pr_alpm_ctl |= PR_ALPM_CTL_USE_DC3CO_IDLE_PROTOCOL;
+ else
+ pr_alpm_ctl &= ~PR_ALPM_CTL_USE_DC3CO_IDLE_PROTOCOL;
+
intel_de_write(display, PR_ALPM_CTL(display, cpu_transcoder),
pr_alpm_ctl);
}
diff --git a/drivers/gpu/drm/i915/display/intel_psr_regs.h b/drivers/gpu/drm/i915/display/intel_psr_regs.h
index 8afbf5a38335..16a9e3af198d 100644
--- a/drivers/gpu/drm/i915/display/intel_psr_regs.h
+++ b/drivers/gpu/drm/i915/display/intel_psr_regs.h
@@ -268,6 +268,7 @@

#define _PR_ALPM_CTL_A 0x60948
#define PR_ALPM_CTL(dev_priv, tran) _MMIO_TRANS2(dev_priv, tran, _PR_ALPM_CTL_A)
+#define PR_ALPM_CTL_USE_DC3CO_IDLE_PROTOCOL BIT(7)
#define PR_ALPM_CTL_ALLOW_LINK_OFF_BETWEEN_AS_SDP_AND_SU BIT(6)
#define PR_ALPM_CTL_RFB_UPDATE_CONTROL BIT(5)
#define PR_ALPM_CTL_AS_SDP_TRANSMISSION_IN_ACTIVE_DISABLE BIT(4)
--
2.43.0