From patchwork Mon Sep 5 13:37:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 12966153 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 78D17ECAAD5 for ; Mon, 5 Sep 2022 13:37:58 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9E92110E3A4; Mon, 5 Sep 2022 13:37:50 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1D2EC10E390 for ; Mon, 5 Sep 2022 13:37:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662385065; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=B/pXD7aQbta8VpoKA60AQUB7mtKPR9zOjvt9Jr1a3+Q=; b=TAEXFSKdCOMS1vzMJIthojwb7Dsq+vrtNALYbSzJa6eGKfY7oRs96sdnH9eaDVpx3JRa36 YG03GLunS95s2dhyvIs91/xqFlG4MiQEDqhSIqQbPVxR1lr7IHxGq0GgAgxolEzSjPIFFk ix5iGo+fT8CrilqgSIAYa8MJhvSPuYk= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-404-9bUeBEtJMxaxnP7S5Yq6Cg-1; Mon, 05 Sep 2022 09:37:44 -0400 X-MC-Unique: 9bUeBEtJMxaxnP7S5Yq6Cg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C105B29ABA14; Mon, 5 Sep 2022 13:37:43 +0000 (UTC) Received: from x1.localdomain.com (unknown [10.39.195.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9E76340D282E; Mon, 5 Sep 2022 13:37:42 +0000 (UTC) From: Hans de Goede To: Patrik Jakobsson Subject: [PATCH 2/3] drm/gma500: Fix crtc_vblank reference leak when userspace queues multiple events Date: Mon, 5 Sep 2022 15:37:37 +0200 Message-Id: <20220905133738.466490-3-hdegoede@redhat.com> In-Reply-To: <20220905133738.466490-1-hdegoede@redhat.com> References: <20220905133738.466490-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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: Hans de Goede , dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The gma500 page-flip code kinda assume that userspace never queues more then 1 vblank event. So basically it assume that userspace does: - page-flip - wait for vblank event - render - page-flip - etc. In the case where userspace would submit 2 page-flips without waiting for the first to finish, the current code will just overwrite gma_crtc->page_flip_event with the event from the 2nd page-flip. Before this patch if page-flips are submitted then drm_crtc_vblank_get() will get called twice, where drm_crtc_vblank_put(crtc) will only be run once, since only 1 event will get reported (the last event set in gma_crtc->page_flip_event). Fix the crtc_vblank reference leak by not calling drm_crtc_vblank_get() when replacing a still set gma_crtc->page_flip_event with a new one. And while at it add a warning for when userspace tries to queue multiple page-flips with events attached which gma500 currently does not support. Note this is not a real fix for the issue of the gma500 code not supporting multiple page-flips events being pending, but it at least improves the situation a bit. Signed-off-by: Hans de Goede --- drivers/gpu/drm/gma500/gma_display.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/gma500/gma_display.c b/drivers/gpu/drm/gma500/gma_display.c index cf038e322164..c4084301afb4 100644 --- a/drivers/gpu/drm/gma500/gma_display.c +++ b/drivers/gpu/drm/gma500/gma_display.c @@ -528,10 +528,13 @@ int gma_crtc_page_flip(struct drm_crtc *crtc, if (event) { spin_lock_irqsave(&dev->event_lock, flags); - - WARN_ON(drm_crtc_vblank_get(crtc) != 0); - - gma_crtc->page_flip_event = event; + if (!gma_crtc->page_flip_event) { + WARN_ON(drm_crtc_vblank_get(crtc) != 0); + gma_crtc->page_flip_event = event; + } else { + drm_warn_once(dev, "page_flip_event already set, gma500 does not support queing multiple events\n"); + gma_crtc->page_flip_event = event; + } spin_unlock_irqrestore(&dev->event_lock, flags); /* Call this locked if we want an event at vblank interrupt. */