From patchwork Fri Jan 17 20:51:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lyude Paul X-Patchwork-Id: 11339741 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 72E4B17EA for ; Fri, 17 Jan 2020 20:52:03 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 507C72083E for ; Fri, 17 Jan 2020 20:52:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ciR4wC0Q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 507C72083E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B2BFB6E044; Fri, 17 Jan 2020 20:52:00 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from us-smtp-delivery-1.mimecast.com (us-smtp-2.mimecast.com [207.211.31.81]) by gabe.freedesktop.org (Postfix) with ESMTPS id D78D76E044 for ; Fri, 17 Jan 2020 20:51:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579294318; 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; bh=zOh5BTGUh3xerGe5YmzlD/g3NoOq6842Kunrgz3bRG8=; b=ciR4wC0QLPL9cy3YfdtmsAaXcvDWkD8bpHxM/kAq32hzf5dedJ/e3WoRXpQ9R21QyfkbvN bO1quwo0YIHFN7sCsW0w5OtsZ7R8vS/eYte6etJp455Drz1XugdpKACW64Za1c3C0pJBK4 YV4W1kOY38KWnrA5zj6UYOqLqIFCFPg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-415-6wyV6EoSNnqPDlIYOLIWfQ-1; Fri, 17 Jan 2020 15:51:57 -0500 X-MC-Unique: 6wyV6EoSNnqPDlIYOLIWfQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 51C98800D5A; Fri, 17 Jan 2020 20:51:55 +0000 (UTC) Received: from malachite.bss.redhat.com (dhcp-10-20-1-90.bss.redhat.com [10.20.1.90]) by smtp.corp.redhat.com (Postfix) with ESMTP id 944A619C7F; Fri, 17 Jan 2020 20:51:50 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org Subject: [PATCH] Revert "drm/dp_mst: Remove VCPI while disabling topology mgr" Date: Fri, 17 Jan 2020 15:51:49 -0500 Message-Id: <20200117205149.97262-1-lyude@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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: , Cc: David Airlie , linux-kernel@vger.kernel.org, Wayne Lin , Sean Paul Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This reverts commit 64e62bdf04ab8529f45ed0a85122c703035dec3a. This commit ends up causing some lockdep splats due to trying to grab the payload lock while holding the mgr's lock: [ 54.010099] [ 54.011765] ====================================================== [ 54.018670] WARNING: possible circular locking dependency detected [ 54.025577] 5.5.0-rc6-02274-g77381c23ee63 #47 Not tainted [ 54.031610] ------------------------------------------------------ [ 54.038516] kworker/1:6/1040 is trying to acquire lock: [ 54.044354] ffff888272af3228 (&mgr->payload_lock){+.+.}, at: drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.054957] [ 54.054957] but task is already holding lock: [ 54.061473] ffff888272af3060 (&mgr->lock){+.+.}, at: drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4 [ 54.071193] [ 54.071193] which lock already depends on the new lock. [ 54.071193] [ 54.080334] [ 54.080334] the existing dependency chain (in reverse order) is: [ 54.088697] [ 54.088697] -> #1 (&mgr->lock){+.+.}: [ 54.094440] __mutex_lock+0xc3/0x498 [ 54.099015] drm_dp_mst_topology_get_port_validated+0x25/0x80 [ 54.106018] drm_dp_update_payload_part1+0xa2/0x2e2 [ 54.112051] intel_mst_pre_enable_dp+0x144/0x18f [ 54.117791] intel_encoders_pre_enable+0x63/0x70 [ 54.123532] hsw_crtc_enable+0xa1/0x722 [ 54.128396] intel_update_crtc+0x50/0x194 [ 54.133455] skl_commit_modeset_enables+0x40c/0x540 [ 54.139485] intel_atomic_commit_tail+0x5f7/0x130d [ 54.145418] intel_atomic_commit+0x2c8/0x2d8 [ 54.150770] drm_atomic_helper_set_config+0x5a/0x70 [ 54.156801] drm_mode_setcrtc+0x2ab/0x833 [ 54.161862] drm_ioctl+0x2e5/0x424 [ 54.166242] vfs_ioctl+0x21/0x2f [ 54.170426] do_vfs_ioctl+0x5fb/0x61e [ 54.175096] ksys_ioctl+0x55/0x75 [ 54.179377] __x64_sys_ioctl+0x1a/0x1e [ 54.184146] do_syscall_64+0x5c/0x6d [ 54.188721] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.194946] [ 54.194946] -> #0 (&mgr->payload_lock){+.+.}: [ 54.201463] [ 54.201463] other info that might help us debug this: [ 54.201463] [ 54.210410] Possible unsafe locking scenario: [ 54.210410] [ 54.217025] CPU0 CPU1 [ 54.222082] ---- ---- [ 54.227138] lock(&mgr->lock); [ 54.230643] lock(&mgr->payload_lock); [ 54.237742] lock(&mgr->lock); [ 54.244062] lock(&mgr->payload_lock); [ 54.248346] [ 54.248346] *** DEADLOCK *** [ 54.248346] [ 54.254959] 7 locks held by kworker/1:6/1040: [ 54.259822] #0: ffff888275c4f528 ((wq_completion)events){+.+.}, at: worker_thread+0x455/0x6e2 [ 54.269451] #1: ffffc9000119beb0 ((work_completion)(&(&dev_priv->hotplug.hotplug_work)->work)){+.+.}, at: worker_thread+0x455/0x6e2 [ 54.282768] #2: ffff888272a403f0 (&dev->mode_config.mutex){+.+.}, at: i915_hotplug_work_func+0x4b/0x2be [ 54.293368] #3: ffffffff824fc6c0 (drm_connector_list_iter){.+.+}, at: i915_hotplug_work_func+0x17e/0x2be [ 54.304061] #4: ffffc9000119bc58 (crtc_ww_class_acquire){+.+.}, at: drm_helper_probe_detect_ctx+0x40/0xfd [ 54.314855] #5: ffff888272a40470 (crtc_ww_class_mutex){+.+.}, at: drm_modeset_lock+0x74/0xe2 [ 54.324385] #6: ffff888272af3060 (&mgr->lock){+.+.}, at: drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4 [ 54.334597] [ 54.334597] stack backtrace: [ 54.339464] CPU: 1 PID: 1040 Comm: kworker/1:6 Not tainted 5.5.0-rc6-02274-g77381c23ee63 #47 [ 54.348893] Hardware name: Google Fizz/Fizz, BIOS Google_Fizz.10139.39.0 01/04/2018 [ 54.357451] Workqueue: events i915_hotplug_work_func [ 54.362995] Call Trace: [ 54.365724] dump_stack+0x71/0x9c [ 54.369427] check_noncircular+0x91/0xbc [ 54.373809] ? __lock_acquire+0xc9e/0xf66 [ 54.378286] ? __lock_acquire+0xc9e/0xf66 [ 54.382763] ? lock_acquire+0x175/0x1ac [ 54.387048] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.393177] ? __mutex_lock+0xc3/0x498 [ 54.397362] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.403492] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.409620] ? drm_dp_dpcd_access+0xd9/0x101 [ 54.414390] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.420517] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.426645] ? intel_digital_port_connected+0x34d/0x35c [ 54.432482] ? intel_dp_detect+0x227/0x44e [ 54.437056] ? ww_mutex_lock+0x49/0x9a [ 54.441242] ? drm_helper_probe_detect_ctx+0x75/0xfd [ 54.446789] ? intel_encoder_hotplug+0x4b/0x97 [ 54.451752] ? intel_ddi_hotplug+0x61/0x2e0 [ 54.456423] ? mark_held_locks+0x53/0x68 [ 54.460803] ? _raw_spin_unlock_irqrestore+0x3a/0x51 [ 54.466347] ? lockdep_hardirqs_on+0x187/0x1a4 [ 54.471310] ? drm_connector_list_iter_next+0x89/0x9a [ 54.476953] ? i915_hotplug_work_func+0x206/0x2be [ 54.482208] ? worker_thread+0x4d5/0x6e2 [ 54.486587] ? worker_thread+0x455/0x6e2 [ 54.490966] ? queue_work_on+0x64/0x64 [ 54.495151] ? kthread+0x1e9/0x1f1 [ 54.498946] ? queue_work_on+0x64/0x64 [ 54.503130] ? kthread_unpark+0x5e/0x5e [ 54.507413] ? ret_from_fork+0x3a/0x50 The proper fix for this is probably cleanup the VCPI allocations when we're enabling the topology, or on the first payload allocation. For now though, let's just revert. Signed-off-by: Lyude Paul Fixes: 64e62bdf04ab ("drm/dp_mst: Remove VCPI while disabling topology mgr") Cc: Sean Paul Cc: Wayne Lin Reviewed-by: Sean Paul --- drivers/gpu/drm/drm_dp_mst_topology.c | 13 ------------- 1 file changed, 13 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 4b74193b89ce..0c585f2bbb69 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3481,7 +3481,6 @@ static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8 dp_link_count) int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state) { int ret = 0; - int i = 0; struct drm_dp_mst_branch *mstb = NULL; mutex_lock(&mgr->lock); @@ -3542,22 +3541,10 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms /* this can fail if the device is gone */ drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0); ret = 0; - mutex_lock(&mgr->payload_lock); memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct drm_dp_payload)); mgr->payload_mask = 0; set_bit(0, &mgr->payload_mask); - for (i = 0; i < mgr->max_payloads; i++) { - struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i]; - - if (vcpi) { - vcpi->vcpi = 0; - vcpi->num_slots = 0; - } - mgr->proposed_vcpis[i] = NULL; - } mgr->vcpi_mask = 0; - mutex_unlock(&mgr->payload_lock); - mgr->payload_id_table_cleared = false; }