From patchwork Sun Jun 3 14:41:08 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 10445403 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0EF69603B4 for ; Sun, 3 Jun 2018 15:19:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F2C6A289ED for ; Sun, 3 Jun 2018 15:19:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E79B128ACB; Sun, 3 Jun 2018 15:19:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id AE810289ED for ; Sun, 3 Jun 2018 15:19:45 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 680746E296; Sun, 3 Jun 2018 15:19:35 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from leontynka.twibright.com (109-183-129-149.tmcz.cz [109.183.129.149]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3DBB96E296 for ; Sun, 3 Jun 2018 15:19:33 +0000 (UTC) Received: from root by leontynka.twibright.com with local (Exim 4.89) (envelope-from ) id 1fPUDA-0003v7-LP; Sun, 03 Jun 2018 16:42:24 +0200 Message-Id: <20180603144224.393326799@twibright.com> User-Agent: quilt/0.63-1 Date: Sun, 03 Jun 2018 16:41:08 +0200 From: Mikulas Patocka To: Mikulas Patocka , Bartlomiej Zolnierkiewicz , Dave Airlie , Bernie Thompson , Ladislav Michl Subject: [PATCH 15/21] udlfb: set optimal write delay References: <20180603144053.875668929@twibright.com> MIME-Version: 1.0 Content-Disposition: inline; filename=udl-defio-delay.patch X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP The default delay 5 jiffies is too much when the kernel is compiled with HZ=100 - it results in jumpy cursor in Xwindow. In order to find out the optimal delay, I benchmarked the driver on 1280x720x30fps video. I found out that with HZ=1000, 10ms is acceptable, but with HZ=250 or HZ=300, we need 4ms, so that the video is played without any frame skips. This patch changes the delay to this value. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org --- include/video/udlfb.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-4.17-rc7/include/video/udlfb.h =================================================================== --- linux-4.17-rc7.orig/include/video/udlfb.h 2018-06-03 13:17:37.000000000 +0200 +++ linux-4.17-rc7/include/video/udlfb.h 2018-06-03 13:17:37.000000000 +0200 @@ -88,7 +88,7 @@ struct dlfb_data { #define MIN_RAW_PIX_BYTES 2 #define MIN_RAW_CMD_BYTES (RAW_HEADER_BYTES + MIN_RAW_PIX_BYTES) -#define DL_DEFIO_WRITE_DELAY 5 /* fb_deferred_io.delay in jiffies */ +#define DL_DEFIO_WRITE_DELAY msecs_to_jiffies(HZ <= 300 ? 4 : 10) /* optimal value for 720p video */ #define DL_DEFIO_WRITE_DISABLE (HZ*60) /* "disable" with long delay */ /* remove these once align.h patch is taken into kernel */