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 6B52DC624DB for ; Thu, 3 Sep 2026 11:01:13 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E71E010E09E; Thu, 3 Sep 2026 11:01:12 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="K7alX/au"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id B9F9810E09E for ; Thu, 3 Sep 2026 11:01:11 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 8BF9C41356; Thu, 3 Sep 2026 11:01:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 44F1B1F000E9; Thu, 3 Sep 2026 11:01:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788433271; bh=TP8RSILQKR+XmNh7aggoTzVxutG4z2BgH2+EbW46NAc=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=K7alX/audswUmw0euJeGHy30G0PeoGylClGIudH9WzPgxeU8AvPWiCre4yVvd/NTA AiZlxO3Dx5Cb6OBVGCwxHzGta6fhN5nPo2IKIDha4durr/PJQw4MhYvlb+VFRMzGCY VntYLNMJeUm2USpO2ykALsDfKrqRZZ65/Scy8rhw7A5IScZT0ZzTWnSnzeGMi/vqnh ECnCzdhBU6v/W0GjRLGwy4cQ/EUZJP0RuT+GSBmOlw7MPm9MDd43aeiuE1puEA0IFc uhD1cb4Jk8lQxxRVrP27joeU+89XEpCnNNrNYXtMepGwBhcGqp/ZYgg+yOoMKmSa+n p28T8z0gaRGrA== From: sashiko-bot@kernel.org Subject: Re: [PATCH] drm/i915/dp: reset HDMI 2.1 PCON FRL state on disconnect To: "Xiao Lu" Cc: intel-gfx@lists.freedesktop.org In-Reply-To: <20260903104400.498178-1-xiaolu.xie@intel.com> References: <20260903104400.498178-1-xiaolu.xie@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 03 Sep 2026 11:01:10 +0000 Message-Id: <20260903110111.44F1B1F000E9@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] FRL training state is not cleared if the EDID is invalidated befor= e a disconnect, causing subsequent FRL training to be skipped permanently. -- commit 666a7a052848216c6b509f4ba1711921db6e5b40 Author: Xiao Lu drm/i915/dp: reset HDMI 2.1 PCON FRL state on disconnect When a DP-to-HDMI 2.1 PCON is disconnected, frl.is_trained remains set from the previous connection. On reconnect, intel_dp_check_frl_training= () checks this flag first and returns early if set, bypassing the entire FRL training sequence entirely. > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i9= 15/display/intel_dp.c > index 113d767e62e9c..3643b6c4c1bc5 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c [ ... ] > +/* > + * On disconnect, the downstream PCON and its HDMI FRL link state are go= ne > + * from the source's perspective. Clear the cached FRL training state so= that > + * intel_dp_check_frl_training() performs a fresh FRL negotiation on the= next > + * connect, rather than skipping training based on stale state. > + */ > +static void > +intel_dp_pcon_disconnect(struct intel_dp *intel_dp) > +{ > + struct intel_display *display =3D to_intel_display(intel_dp); > + > + if (!intel_dp_is_hdmi_2_1_sink(intel_dp)) > + return; [Severity: High] Can this early return prevent clearing the FRL state if the EDID is invalid= ated before a disconnect? If a transient I2C-over-AUX error occurs during a background reprobe while the monitor is still physically connected, it can cause intel_dp_set_edid() to fail. This failure causes drm_edid_connector_update() to be called with NULL, which clears connector->base.display_info and sets is_hdmi to false. If the monitor is subsequently unplugged, triggering a disconnect, this function returns early because intel_dp_is_hdmi_2_1_sink() evaluates to false. The frl.is_trained flag remains true. When the monitor is reconnected, intel_dp_check_frl_training() skips training because is_trained is still true, leading to a permanent blank screen or severely limited resolution until a driver reload or reboot. Should the state clearing be performed unconditionally, since the current sink capabilities can be stale or invalidated? > + > + drm_dbg_kms(display->drm, > + "PCON HDMI2.1 sink disconnected, resetting FRL state (was trained = at %d Gbps)\n", > + intel_dp->frl.trained_rate_gbps); > + intel_dp->frl.is_trained =3D false; > + intel_dp->frl.trained_rate_gbps =3D 0; > +} --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260903104400.4981= 78-1-xiaolu.xie@intel.com?part=3D1