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 B6AE7C43458 for ; Tue, 30 Jun 2026 10:47:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 600C910E4C7; Tue, 30 Jun 2026 10:47:08 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="nqw/pA79"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) by gabe.freedesktop.org (Postfix) with ESMTPS id DCC0010E4C7; Tue, 30 Jun 2026 10:47:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1782816427; x=1814352427; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=E2IZ2NcKyvZ8Ps2OcVQu5ZgaoCJVLbeo45JHCtf8Qnw=; b=nqw/pA796ZbLMJQVo4kt3oaQHfT7RoVCdbSkJwG/xUtRo2W054OoUfjB RkAqzjnuwdy3iMXn48kRK0A2bc5teAqLLtA+cyPFzvHMtkioGckKLoQEa FQviCLtQW2SLrQazcBp6DQc+SmzLbB3q7F1Jf5W0ABy5ZFCe8IY7rAuEa m30vuDFgjdZTUTsvIakhWOja0sv1OHVWZHOX92SnO7ZV9LfOE/Np2Nzpy 7CVSPKH6+zsfopv5hmuOAhS0rJ0q3PS4L5ghjj9ntKHddgeYvi23hPvR5 S3lFKy1q79Ao5vlsFTNaKwgderuvvgLA/i8N7g4z4zk6iaF5tDZAtyHfB w==; X-CSE-ConnectionGUID: +GUoKjIrQH293G6dH0dPMg== X-CSE-MsgGUID: zDU6aN1FSzW871ZuGwHp9g== X-IronPort-AV: E=McAfee;i="6800,10657,11832"; a="87438790" X-IronPort-AV: E=Sophos;i="6.24,233,1774335600"; d="scan'208";a="87438790" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jun 2026 03:47:07 -0700 X-CSE-ConnectionGUID: KbJVoEIsR/qc+xI2RqotFQ== X-CSE-MsgGUID: qQflYbSETQeeNI6x/UN6NQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,233,1774335600"; d="scan'208";a="249591986" Received: from ijarvine-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.245.148]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jun 2026 03:47:03 -0700 From: Jani Nikula To: mei.fan.liou@intel.com, Rodrigo Vivi Cc: Joonas Lahtinen , Tvrtko Ursulin , David Airlie , Simona Vetter , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, "LIOU, Mei Fan" Subject: Re: [PATCH] drm/i915: add disable_edp module parameter to skip phantom eDP init In-Reply-To: <20260630102845.2678707-1-mei.fan.liou@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland References: <20260630102845.2678707-1-mei.fan.liou@intel.com> Date: Tue, 30 Jun 2026 13:47:01 +0300 Message-ID: <50700395af210f0e5ca0c5e8306cda41b077f43a@intel.com> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, 30 Jun 2026, mei.fan.liou@intel.com wrote: > From: "LIOU, Mei Fan" > > Some platforms have BIOS/VBT that declares an eDP panel present while > no physical panel is connected. This causes intel_edp_init_connector() > to spend ~6 seconds waiting on PPS power sequencer and AUX channel > timeouts before failing gracefully. Which platforms? This should not be the case. > Introduce a new boolean module parameter 'disable_edp' (default: false) > that allows users to skip eDP connector initialization entirely. When > set, the driver logs an informational message and returns false early > from intel_edp_init_connector(), bypassing all PPS/AUX probing. I'm fine with adding module parameters for *debugging*. I'm not fine with adding module parameters for regular use cases. If there are issues out there, they should be root caused and fixed, worst case with a quirk, but roughly never with a new module parameter. You can also disable connectors using the video= parameter and connector name, e.g. video=eDP-1:d or something. Making this work (if it doesn't) should be preferred over adding new module parameters. And even here, root causing and fixing is preferred. > This is modeled after the existing 'disable_display' parameter and > is intended as a workaround for headless or display-less deployments > where the BIOS incorrectly advertises an internal panel. "headless" and "display-less" are super ambiguous, given the amount of possible alternatives. You might not have display IP at all, or you could have everything except a display connected, or everything in between. But VBT advertizing eDP but it not being connected is not a scenario that we should have, and either the VBT or the whole setup is bonkers. Please file a bug as described at [1], and be sure to attach the dmesg with debugs, and the VBT. BR, Jani. [1] https://drm.pages.freedesktop.org/intel-docs/how-to-file-i915-bugs.html > > Signed-off-by: LIOU, Mei Fan > --- > drivers/gpu/drm/i915/display/intel_display_params.c | 3 +++ > drivers/gpu/drm/i915/display/intel_display_params.h | 1 + > drivers/gpu/drm/i915/display/intel_dp.c | 7 +++++++ > 3 files changed, 11 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c > index 2aed110c5b09..8d47d19b1667 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_params.c > +++ b/drivers/gpu/drm/i915/display/intel_display_params.c > @@ -102,6 +102,9 @@ intel_display_param_named_unsafe(force_reset_modeset_test, bool, 0400, > intel_display_param_named(disable_display, bool, 0400, > "Disable display (default: false)"); > > +intel_display_param_named(disable_edp, bool, 0400, > + "Disable eDP panel init, skips PPS/AUX probing when VBT declares eDP but no panel is present (default: false)"); > + > intel_display_param_named(verbose_state_checks, bool, 0400, > "Enable verbose logs (ie. WARN_ON()) in case of unexpected hw state conditions."); > > diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h > index b95ecf728daa..98ab0d753dab 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_params.h > +++ b/drivers/gpu/drm/i915/display/intel_display_params.h > @@ -41,6 +41,7 @@ struct drm_printer; > param(bool, load_detect_test, false, 0600) \ > param(bool, force_reset_modeset_test, false, 0600) \ > param(bool, disable_display, false, 0400) \ > + param(bool, disable_edp, false, 0400) \ > param(bool, verbose_state_checks, true, 0400) \ > param(bool, nuclear_pageflip, false, 0400) \ > param(bool, enable_dp_mst, true, 0600) \ > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > index 85d3aa3b9894..c6293a1b3840 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -7214,6 +7214,13 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, > if (!intel_dp_is_edp(intel_dp)) > return true; > > + if (display->params.disable_edp) { > + drm_info(display->drm, > + "[ENCODER:%d:%s] eDP disabled by module parameter, skipping init\n", > + encoder->base.base.id, encoder->base.name); > + return false; > + } > + > /* > * On IBX/CPT we may get here with LVDS already registered. Since the > * driver uses the only internal power sequencer available for both -- Jani Nikula, Intel