From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 40DEFE8B39D for ; Wed, 4 Feb 2026 05:18:38 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C4A0610E23C; Wed, 4 Feb 2026 05:18:37 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="lcRPmC9w"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5ABA910E23C; Wed, 4 Feb 2026 05:18:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1770182316; x=1801718316; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=bEjPMFZfzAtaeuEnLNRkgLMossg6RuGKZmGPvunkqsA=; b=lcRPmC9w0HI67yobrKFNjg3fcqfOcAcyialKYW0zFgkFlUilP+Nv/eOA FGp+JzJkr+HFM9EmWG/IRX9nGMk+BSmfMS5eCi1gfcYYNz+ALWJfYaZ+i 5lamTNHBrEGe+XVm8f+LntYsJ+jXgWShiiSOHxQMbY2lLwdvNgygIU3/7 YUToo1mWHeLIHWE1KVrtx6lRva5i0Av8CIO5e+ZkGXgOpmFXspUENszga SE+OAxfgTwXVBdXRHCrWow+oJo7wli7tfoH+OojUye1FRKJxpiz7R7+ks 8sLFS7bbvEZPoyEHA13BUz1PPOb0RrGke4Kld8ZEGkW+n5Sx009tBTS8Y w==; X-CSE-ConnectionGUID: DrJZhN0kTduZwh11qzyOdw== X-CSE-MsgGUID: hM3rz1+uQFmvcGWufoKy6A== X-IronPort-AV: E=McAfee;i="6800,10657,11691"; a="82102819" X-IronPort-AV: E=Sophos;i="6.21,272,1763452800"; d="scan'208";a="82102819" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2026 21:18:36 -0800 X-CSE-ConnectionGUID: 0Sl7Rl22Rg+pzzP5I0uzFA== X-CSE-MsgGUID: YSW69dvJQzWeSuyeF5mkng== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,272,1763452800"; d="scan'208";a="210127475" Received: from srr4-3-linux-103-aknautiy.iind.intel.com ([10.223.34.160]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2026 21:18:34 -0800 From: Ankit Nautiyal To: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Cc: jouni.hogander@intel.com, ville.syrjala@linux.intel.com, animesh.manna@intel.com, michal.grzelak@intel.com, Ankit Nautiyal Subject: [RESEND 1/5] drm/i915/alpm: Compute LOBF late after guardband is already determined Date: Wed, 4 Feb 2026 10:32:46 +0530 Message-ID: <20260204050250.762718-2-ankit.k.nautiyal@intel.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20260204050250.762718-1-ankit.k.nautiyal@intel.com> References: <20260204050250.762718-1-ankit.k.nautiyal@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Currently intel_alpm_lobf_compute_config() tries to account for guardband +SCL requirements during encoder->compute_config() phase, even before guardband is computed. Also, LOBF depends on crtc_state->has_psr which can be modified in encoder->compute_config_late(). Account for lobf requirements while optimizing the guardband and add checks for final guardband in encoder->compute_config_late() phase after the guardband and the final state of crtc_state->has_psr are already computed. Use crtc_state->vrr.guardband and crtc_state->set_context_latency for the computation and add more documentation for the dependency of first sdp position, guardband, set context latency and wake lines. v2: Add helper to use min guardband required for lobf. v3: Remove unrelated inadvertent changes. (Michał) v4: Add a #FIXME note for computing wakelines based on feature. (Jouni) Bspec:71041 Signed-off-by: Ankit Nautiyal Reviewed-by: Michał Grzelak --- drivers/gpu/drm/i915/display/intel_alpm.c | 70 ++++++++++++++++++----- drivers/gpu/drm/i915/display/intel_alpm.h | 3 + drivers/gpu/drm/i915/display/intel_dp.c | 2 + drivers/gpu/drm/i915/display/intel_vrr.c | 2 + 4 files changed, 63 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c index 7ce8c674bb03..055184a3c7d5 100644 --- a/drivers/gpu/drm/i915/display/intel_alpm.c +++ b/drivers/gpu/drm/i915/display/intel_alpm.c @@ -15,6 +15,7 @@ #include "intel_dp_aux.h" #include "intel_psr.h" #include "intel_psr_regs.h" +#include "intel_vrr.h" #define SILENCE_PERIOD_MIN_TIME 80 #define SILENCE_PERIOD_MAX_TIME 180 @@ -248,14 +249,65 @@ bool intel_alpm_compute_params(struct intel_dp *intel_dp, return true; } +int intel_alpm_lobf_min_guardband(struct intel_crtc_state *crtc_state) +{ + struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode; + int first_sdp_position = adjusted_mode->crtc_vtotal - + adjusted_mode->crtc_vsync_start; + int waketime_in_lines; + + /* + * #FIXME: Need to check if io_wake_lines or aux_less_wake_lines + * is applicable. Currently this information is not readily + * available in crtc_state, so max will suffice for now. + */ + waketime_in_lines = max(crtc_state->alpm_state.io_wake_lines, + crtc_state->alpm_state.aux_less_wake_lines); + + if (!crtc_state->has_lobf) + return 0; + + return first_sdp_position + waketime_in_lines + crtc_state->set_context_latency; +} + +void intel_alpm_lobf_compute_config_late(struct intel_dp *intel_dp, + struct intel_crtc_state *crtc_state) +{ + struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode; + int waketime_in_lines, first_sdp_position; + + if (!crtc_state->has_lobf) + return; + + /* + * LOBF can only be enabled if the time from the start of the SCL+Guardband + * window to the position of the first SDP is greater than the time it takes + * to wake the main link. + * + * Position of first sdp : vsync_start + * start of scl + guardband : vtotal - (scl + guardband) + * time in lines to wake main link : waketime_in_lines + * + * Position of first sdp - start of (scl + guardband) > time in lines to wake main link + * vsync_start - (vtotal - (scl + guardband)) > waketime_in_lines + * vsync_start - vtotal + scl + guardband > waketime_in_lines + * scl + guardband > waketime_in_lines + (vtotal - vsync_start) + */ + first_sdp_position = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vsync_start; + if (intel_alpm_aux_less_wake_supported(intel_dp)) + waketime_in_lines = crtc_state->alpm_state.io_wake_lines; + else + waketime_in_lines = crtc_state->alpm_state.aux_less_wake_lines; + + crtc_state->has_lobf = (crtc_state->set_context_latency + crtc_state->vrr.guardband) > + (first_sdp_position + waketime_in_lines); +} + void intel_alpm_lobf_compute_config(struct intel_dp *intel_dp, struct intel_crtc_state *crtc_state, struct drm_connector_state *conn_state) { struct intel_display *display = to_intel_display(intel_dp); - struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode; - int waketime_in_lines, first_sdp_position; - int context_latency, guardband; if (intel_dp->alpm.lobf_disable_debug) { drm_dbg_kms(display->drm, "LOBF is disabled by debug flag\n"); @@ -288,17 +340,7 @@ void intel_alpm_lobf_compute_config(struct intel_dp *intel_dp, if (!intel_alpm_compute_params(intel_dp, crtc_state)) return; - context_latency = adjusted_mode->crtc_vblank_start - adjusted_mode->crtc_vdisplay; - guardband = adjusted_mode->crtc_vtotal - - adjusted_mode->crtc_vdisplay - context_latency; - first_sdp_position = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vsync_start; - if (intel_alpm_aux_less_wake_supported(intel_dp)) - waketime_in_lines = crtc_state->alpm_state.io_wake_lines; - else - waketime_in_lines = crtc_state->alpm_state.aux_less_wake_lines; - - crtc_state->has_lobf = (context_latency + guardband) > - (first_sdp_position + waketime_in_lines); + crtc_state->has_lobf = true; } static void lnl_alpm_configure(struct intel_dp *intel_dp, diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h b/drivers/gpu/drm/i915/display/intel_alpm.h index c6a4ec5b9561..b698979d1f13 100644 --- a/drivers/gpu/drm/i915/display/intel_alpm.h +++ b/drivers/gpu/drm/i915/display/intel_alpm.h @@ -38,4 +38,7 @@ bool intel_alpm_is_alpm_aux_less(struct intel_dp *intel_dp, const struct intel_crtc_state *crtc_state); void intel_alpm_disable(struct intel_dp *intel_dp); bool intel_alpm_get_error(struct intel_dp *intel_dp); +void intel_alpm_lobf_compute_config_late(struct intel_dp *intel_dp, + struct intel_crtc_state *crtc_state); +int intel_alpm_lobf_min_guardband(struct intel_crtc_state *crtc_state); #endif diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index e2fd01d1a1e4..2b8f43e21174 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -7163,6 +7163,8 @@ int intel_dp_compute_config_late(struct intel_encoder *encoder, if (ret) return ret; + intel_alpm_lobf_compute_config_late(intel_dp, crtc_state); + return 0; } diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c index 9d814cc2d608..00ca76dbdd6c 100644 --- a/drivers/gpu/drm/i915/display/intel_vrr.c +++ b/drivers/gpu/drm/i915/display/intel_vrr.c @@ -6,6 +6,7 @@ #include +#include "intel_alpm.h" #include "intel_crtc.h" #include "intel_de.h" #include "intel_display_regs.h" @@ -520,6 +521,7 @@ int intel_vrr_compute_optimized_guardband(struct intel_crtc_state *crtc_state) if (intel_crtc_has_dp_encoder(crtc_state)) { guardband = max(guardband, intel_psr_min_guardband(crtc_state)); guardband = max(guardband, intel_dp_sdp_min_guardband(crtc_state, true)); + guardband = max(guardband, intel_alpm_lobf_min_guardband(crtc_state)); } return guardband; -- 2.45.2