From patchwork Thu Apr 4 23:35:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lyude Paul X-Patchwork-Id: 13618305 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 EE1DBCD1284 for ; Thu, 4 Apr 2024 23:37:51 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6A77A11365A; Thu, 4 Apr 2024 23:37:50 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="HpS2sHpu"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id D42CB113674 for ; Thu, 4 Apr 2024 23:37:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1712273865; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8ypcfm8f/5CHd95kPjs/R9gdMDLtVxLsgq1JjJ/htFQ=; b=HpS2sHpuUYeERA6wfmN5bafwHXKKhAQUmLr7mfURB43wbPrHfGowmX0tdMGPtXu5TBiDH5 HoFi55qSmhuCe8E5n1zjHd3nlAMbnOFv2IkB3u8GuxYskDrDl5rsHZfvUmClSm+RnzfBYD hmiuT/Sb7yq2rX7zsu3KOcS0UNeQ7Ok= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-199-6pLPrQW0MIqKHr5AwYWBFw-1; Thu, 04 Apr 2024 19:37:41 -0400 X-MC-Unique: 6pLPrQW0MIqKHr5AwYWBFw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7E8858007A3; Thu, 4 Apr 2024 23:37:41 +0000 (UTC) Received: from chopper.lyude.net (unknown [10.22.8.53]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9873F8173; Thu, 4 Apr 2024 23:37:40 +0000 (UTC) From: Lyude Paul To: nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org Cc: Karol Herbst , Danilo Krummrich , David Airlie , Daniel Vetter , linux-kernel@vger.kernel.org (open list) Subject: [PATCH 1/2] drm/nouveau/kms/nv50-: Disable AUX bus for disconnected DP ports Date: Thu, 4 Apr 2024 19:35:53 -0400 Message-ID: <20240404233736.7946-2-lyude@redhat.com> In-Reply-To: <20240404233736.7946-1-lyude@redhat.com> References: <20240404233736.7946-1-lyude@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" GSP has its own state for keeping track of whether or not a given display connector is plugged in or not, and enforces this state on the driver. In particular, AUX transactions on a DisplayPort connector which GSP says is disconnected can never succeed - and can in some cases even cause unexpected timeouts, which can trickle up to cause other problems. A good example of this is runtime power management: where we can actually get stuck trying to resume the GPU if a userspace application like fwupd tries accessing a drm_aux_dev for a disconnected port. This was an issue I hit a few times with my Slimbook Executive 16 - where trying to offload something to the discrete GPU would wake it up, and then potentially cause it to timeout as fwupd tried to immediately access the dp_aux_dev nodes for nouveau. Likewise: we don't really have any cases I know of where we'd want to ignore this state and try an aux transaction anyway - and failing pointless aux transactions immediately can even speed things up. So - let's start enabling/disabling the aux bus in nouveau_dp_detect() to fix this. We enable the aux bus during connector probing, and leave it enabled if we discover something is actually on the connector. Otherwise, we just shut it off. This should fix some people's runtime PM issues (like myself), and also get rid of quite of a lot of GSP error spam in dmesg. Signed-off-by: Lyude Paul Reviewed-by: Dave Airlie --- drivers/gpu/drm/nouveau/nouveau_dp.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/nouveau/nouveau_dp.c b/drivers/gpu/drm/nouveau/nouveau_dp.c index fb06ee17d9e54..8b1be7dd64ebe 100644 --- a/drivers/gpu/drm/nouveau/nouveau_dp.c +++ b/drivers/gpu/drm/nouveau/nouveau_dp.c @@ -232,6 +232,9 @@ nouveau_dp_detect(struct nouveau_connector *nv_connector, dpcd[DP_DPCD_REV] != 0) return NOUVEAU_DP_SST; + // Ensure that the aux bus is enabled for probing + drm_dp_dpcd_set_powered(&nv_connector->aux, true); + mutex_lock(&nv_encoder->dp.hpd_irq_lock); if (mstm) { /* If we're not ready to handle MST state changes yet, just @@ -293,6 +296,13 @@ nouveau_dp_detect(struct nouveau_connector *nv_connector, if (mstm && !mstm->suspended && ret != NOUVEAU_DP_MST) nv50_mstm_remove(mstm); + /* GSP doesn't like when we try to do aux transactions on a port it considers disconnected, + * and since we don't really have a usecase for that anyway - just disable the aux bus here + * if we've decided the connector is disconnected + */ + if (ret == NOUVEAU_DP_NONE) + drm_dp_dpcd_set_powered(&nv_connector->aux, false); + mutex_unlock(&nv_encoder->dp.hpd_irq_lock); return ret; }