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: 10445419 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 E58B7603D7 for ; Sun, 3 Jun 2018 15:20:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CE30728740 for ; Sun, 3 Jun 2018 15:20:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B6C6428AF9; Sun, 3 Jun 2018 15:20:06 +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=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7677528740 for ; Sun, 3 Jun 2018 15:20:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751716AbeFCPUF (ORCPT ); Sun, 3 Jun 2018 11:20:05 -0400 Received: from 109-183-129-149.tmcz.cz ([109.183.129.149]:59096 "EHLO leontynka.twibright.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751706AbeFCPUE (ORCPT ); Sun, 3 Jun 2018 11:20:04 -0400 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 Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org 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 Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org 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(-) -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html 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