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 DA48CC88E75 for ; Tue, 15 Sep 2026 19:01:09 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0A8E710F13C; Tue, 15 Sep 2026 19:01:06 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="TVhdWlgZ"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id AEB4710F0DA; Tue, 15 Sep 2026 19:01:04 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 90BB960142; Tue, 15 Sep 2026 19:01:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 579041F0089C; Tue, 15 Sep 2026 19:01:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789498863; bh=aAtHTiiwEGDc+I3dJKuf2MW6AH765zePtamAifVw7sM=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=TVhdWlgZY3z0gaEJujQOp+k4P1wkSbVHufjnlE0orSLovVIzkP7y7HB/XyYgYShuP PLapINhxiJMjIferD5SQJZ7yQVrl+70RGHC/ot3k5rqOQHtrhKTjFXm7hbtujMeRWU 2iCF6haI1unABotnfNn6JUewkXnr5Nz/mmuGlgQtwZGLAHGfEOEb3MLrykmW4Mknx/ uuqZ8fbxJ/cYz9JFoLWw0evw9p7pOBd3YDygNWul0AppO8Vctoc/yRCPXf+7URyllr sOe7+KjLp7WEgJ/YKjMACJWh3FcgWYyPmoaLNQ2QjVHGjJ4wD0xvgNTzNPf5sK+v7I +2EQwdbixk7cw== From: sashiko-bot@kernel.org Subject: Re: [PATCH v6 18/18] drm/i915/alpm: Disallow ALPM for UHBR link rate To: "Animesh Manna" Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, intel-xe@lists.freedesktop.org In-Reply-To: <20260915180449.277933-19-animesh.manna@intel.com> References: <20260915180449.277933-1-animesh.manna@intel.com> <20260915180449.277933-19-animesh.manna@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 15 Sep 2026 19:01:00 +0000 Message-Id: <20260915190102.579041F0089C@smtp.kernel.org> 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: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] drm/i915: ALPM and Panel Replay stay enabled with zeroed params on= external DP UHBR -- commit 735fad731be8c8f544adf68949ae9f43b62606f2 Author: Animesh Manna drm/i915/alpm: Disallow ALPM for UHBR link rate This commit attempts to reject ALPM parameter computation for external DP running at a UHBR rate on NVL platforms. eDP is explicitly excluded from th= is check to keep eDP ALPM working at all link rates. > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/= i915/display/intel_alpm.c > index 84777c8d31bb4..51805a6bca867 100644 > --- a/drivers/gpu/drm/i915/display/intel_alpm.c > +++ b/drivers/gpu/drm/i915/display/intel_alpm.c > @@ -453,6 +453,12 @@ bool intel_alpm_compute_params(struct intel_dp *inte= l_dp, > int precharge =3D intel_dp_aux_fw_sync_len(intel_dp) - preamble; > u8 max_wake_lines; > =20 > + /* DP2.1 ALPM is not supported on UHBR (128b/132b) link rates on NVL. */ > + if (DISPLAY_VER(display) =3D=3D 35 && > + !intel_crtc_has_type(crtc_state, INTEL_OUTPUT_EDP) && > + intel_dp_is_uhbr(crtc_state)) > + return false; > + [Severity: High] Does returning false here successfully prevent ALPM and Panel Replay from b= eing enabled on external DP? Looking at _panel_replay_compute_config() in drivers/gpu/drm/i915/display/intel_psr.c, there is an early return for non-= eDP displays: if (!intel_dp_is_edp(intel_dp)) return true; /* Remaining checks are for eDP only */ if (!crtc_state->has_alpm) return false; Because of this early return, the failed ALPM parameter computation is bypa= ssed for external DP. Later in intel_sel_update_config_valid(), has_alpm is unconditionally overwritten: crtc_state->has_alpm =3D intel_alpm_is_possible(intel_dp); return true; Could this sequence leave ALPM and Panel Replay enabled with uninitialized (zeroed) wake lines and times, potentially violating DP specifications and preventing the external display from waking up correctly? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260915180449.2779= 33-1-animesh.manna@intel.com?part=3D18