From patchwork Sun Jun 3 14:41:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 10445425 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 AD3DF6022E for ; Sun, 3 Jun 2018 15:20:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9B27528740 for ; Sun, 3 Jun 2018 15:20:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 90006289FF; Sun, 3 Jun 2018 15:20:22 +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 41A5628740 for ; Sun, 3 Jun 2018 15:20:22 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7A32C6E292; Sun, 3 Jun 2018 15:20:04 +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 4CE3D6E2C1 for ; Sun, 3 Jun 2018 15:20:03 +0000 (UTC) Received: from root by leontynka.twibright.com with local (Exim 4.89) (envelope-from ) id 1fPUD9-0003tX-L6; Sun, 03 Jun 2018 16:42:23 +0200 Message-Id: <20180603144223.332517485@twibright.com> User-Agent: quilt/0.63-1 Date: Sun, 03 Jun 2018 16:41:05 +0200 From: Mikulas Patocka To: Mikulas Patocka , Bartlomiej Zolnierkiewicz , Dave Airlie , Bernie Thompson , Ladislav Michl Subject: [PATCH 12/21] udlfb: fix display corruption of the last line References: <20180603144053.875668929@twibright.com> MIME-Version: 1.0 Content-Disposition: inline; filename=udl-append-zero-4.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 displaylink hardware has such a peculiarity that it doesn't render a command until next command is received. This produces occasional corruption, such as when setting 22x11 font on the console, only the first line of the cursor will be blinking if the cursor is located at some specific columns. When we end up with a repeating pixel, the driver has a bug that it leaves one uninitialized byte after the command (and this byte is enough to flush the command and render it - thus it fixes the screen corruption), however whe we end up with a non-repeating pixel, there is no byte appended and this results in temporary screen corruption. This patch fixes the screen corruption by always appending a byte 0xAF at the end of URB. It also removes the uninitialized byte. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org --- drivers/video/fbdev/udlfb.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) Index: linux-4.17-rc7/drivers/video/fbdev/udlfb.c =================================================================== --- linux-4.17-rc7.orig/drivers/video/fbdev/udlfb.c 2018-05-31 14:43:13.000000000 +0200 +++ linux-4.17-rc7/drivers/video/fbdev/udlfb.c 2018-05-31 14:46:03.000000000 +0200 @@ -27,6 +27,7 @@ #include #include #include +#include #include