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 98CA7CA600B for ; Thu, 8 Oct 2026 07:38:18 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F15AE10FCBE; Thu, 8 Oct 2026 07:38:17 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="KR4rDzTn"; 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 A3CFC10FCBE for ; Thu, 8 Oct 2026 07:38:16 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 8C141419C7; Thu, 8 Oct 2026 07:38:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4FFCE1F000FF; Thu, 8 Oct 2026 07:38:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791445096; bh=42tEfSCwrEQdTCVPUj466kCjGMPLnBr3HCBYWUS+8PA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=KR4rDzTnW/+PIkHrk8m3UPx+f25GG0yv8fpDYUU13qD8Y+nb/QQ2dbcj00lGXY2rT JMxTJ/KWEWVAM2SUXdYsEW4qIVW9lbMZFr9/kt8a33t2RsZ9fMrBtf/u8sW5NZTCi4 iZ7pttPrQe9NxdVGubRQyX46QcvYxfJYXqXDhY/cZn/eSvhfiFUma8MQ5bUJeFug5K TdcxEuwFrK1osirkqJfFyWd/ZgMZSZvNDAC2fuHmSyYHbC2CYcU/ak+EIYPaJ3eTAy O4IxvADX0rpA/TQg3u8wwhNu3WnQdxEaMd/z4nI1nP7BENC8NADOg9gvHACzK/OHok 0+EPqwK1YCXAA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH] drm/amd/display: Increase the HDMI HPD disconnect filter time To: 2564278112@qq.com Cc: dri-devel@lists.freedesktop.org In-Reply-To: References: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 08 Oct 2026 07:38:15 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Medium] drm/amd/display: HDMI HPD disconnect filter masks valid KVM puls= es -- commit 56a856b6f885a6969be27edf739c5c17d243d79b Author: Wang Jiang drm/amd/display: Increase the HDMI HPD disconnect filter time This commit raises the DVI and HDMI HPD disconnect filter time from 100ms to 800ms to hide bouncing hotplug signals when sinks reconfigure. > diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_hpd.c b/d= rivers/gpu/drm/amd/display/dc/link/protocols/link_hpd.c > --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_hpd.c > +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_hpd.c > @@ -82,8 +82,12 @@ bool program_hpd_filter(const struct dc_link *link) > case SIGNAL_TYPE_HDMI_TYPE_A: > case SIGNAL_TYPE_HDMI_FRL: > /* Program hpd filter */ > + /* Some HDMI/DVI sinks drive HPD low for a few hundred ms while > + * they reconfigure; 100ms is not enough to hide that bounce, > + * which is then reported as a fake unplug/plug pair. > + */ > delay_on_connect_in_ms =3D 500; > - delay_on_disconnect_in_ms =3D 100; > + delay_on_disconnect_in_ms =3D 800; [Severity: Medium] Will this 800ms filter in program_hpd_filter() mask legitimate hotplug puls= es from KVM switches or AV receivers? Standard HPD low pulses used by these devices to indicate a configuration change are typically between 100ms and 500ms. Because this filter is progra= mmed in hardware, an 800ms threshold completely hides these valid pulses from the CPU, meaning the HPD interrupt never fires. Could this cause the driver to miss valid hotplug events when users switch inputs, resulting in blank screens or incorrect video modes because EDID and HDCP are not renegotiated? > break; > case SIGNAL_TYPE_DISPLAY_PORT: > case SIGNAL_TYPE_DISPLAY_PORT_MST: --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/tencent_B4299278015= 532212E7D2E624FA23C09C90A@qq.com?part=3D1