From patchwork Sun Jun 3 15:46:29 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 10445429 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 668A0601BC for ; Sun, 3 Jun 2018 15:46:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5787A285FD for ; Sun, 3 Jun 2018 15:46:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 49EEA287D5; Sun, 3 Jun 2018 15:46:38 +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 EF8D8285FD for ; Sun, 3 Jun 2018 15:46:37 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 29C926E2A7; Sun, 3 Jun 2018 15:46:35 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by gabe.freedesktop.org (Postfix) with ESMTPS id 935976E2A7 for ; Sun, 3 Jun 2018 15:46:33 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6F4938151D6F; Sun, 3 Jun 2018 15:46:32 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0F2C11D088; Sun, 3 Jun 2018 15:46:31 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id w53FkVwq015435; Sun, 3 Jun 2018 11:46:31 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id w53FkTEP015427; Sun, 3 Jun 2018 11:46:30 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Sun, 3 Jun 2018 11:46:29 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Bartlomiej Zolnierkiewicz , Dave Airlie , Bernie Thompson , Ladislav Michl Subject: [PATCH] fb: fix lost console when the user unplugs a USB adapter Message-ID: User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Sun, 03 Jun 2018 15:46:32 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Sun, 03 Jun 2018 15:46:32 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mpatocka@redhat.com' RCPT:'' 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 I have a USB display adapter using the udlfb driver and I use it on an ARM board that doesn't have any graphics card. When I plug the adapter in, the console is properly displayed, however when I unplug and re-plug the adapter, the console is not displayed and I can't access it until I reboot the board. The reason is this: When the adapter is unplugged, dlfb_usb_disconnect calls unlink_framebuffer, then it waits until the reference count drops to zero and then it deallocates the framebuffer. However, the console that is attached to the framebuffer device keeps the reference count non-zero, so the framebuffer device is never destroyed. When the USB adapter is plugged again, it creates a new device /dev/fb1 and the console is not attached to it. This patch fixes the bug by unbinding the console from unlink_framebuffer. The code to unbind the console is moved from do_unregister_framebuffer to a function unbind_console. When the console is unbound, the reference count drops to zero and the udlfb driver frees the framebuffer. When the adapter is plugged back, a new framebuffer is created and the console is attached to it. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/video/fbdev/core/fbmem.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) Index: linux-4.16.12/drivers/video/fbdev/core/fbmem.c =================================================================== --- linux-4.16.12.orig/drivers/video/fbdev/core/fbmem.c 2018-05-26 06:13:20.000000000 +0200 +++ linux-4.16.12/drivers/video/fbdev/core/fbmem.c 2018-05-26 06:13:20.000000000 +0200 @@ -1805,12 +1805,12 @@ static int do_register_framebuffer(struc return 0; } -static int do_unregister_framebuffer(struct fb_info *fb_info) +static int unbind_console(struct fb_info *fb_info) { struct fb_event event; - int i, ret = 0; + int ret; + int i = fb_info->node; - i = fb_info->node; if (i < 0 || i >= FB_MAX || registered_fb[i] != fb_info) return -EINVAL; @@ -1825,6 +1825,16 @@ static int do_unregister_framebuffer(str unlock_fb_info(fb_info); console_unlock(); + return ret; +} + +static int do_unregister_framebuffer(struct fb_info *fb_info) +{ + struct fb_event event; + int ret; + + ret = unbind_console(fb_info); + if (ret) return -EINVAL; @@ -1835,7 +1845,7 @@ static int do_unregister_framebuffer(str (fb_info->pixmap.flags & FB_PIXMAP_DEFAULT)) kfree(fb_info->pixmap.addr); fb_destroy_modelist(&fb_info->modelist); - registered_fb[i] = NULL; + registered_fb[fb_info->node] = NULL; num_registered_fb--; fb_cleanup_device(fb_info); event.info = fb_info; @@ -1860,6 +1870,9 @@ int unlink_framebuffer(struct fb_info *f device_destroy(fb_class, MKDEV(FB_MAJOR, i)); fb_info->dev = NULL; } + + unbind_console(fb_info); + return 0; } EXPORT_SYMBOL(unlink_framebuffer);