From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC618C282E1 for ; Fri, 24 May 2019 08:55:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A35562184B for ; Fri, 24 May 2019 08:55:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="A810gJ8G" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390336AbfEXIzT (ORCPT ); Fri, 24 May 2019 04:55:19 -0400 Received: from mail-ed1-f68.google.com ([209.85.208.68]:41667 "EHLO mail-ed1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390046AbfEXIyg (ORCPT ); Fri, 24 May 2019 04:54:36 -0400 Received: by mail-ed1-f68.google.com with SMTP id m4so13313760edd.8 for ; Fri, 24 May 2019 01:54:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=P4e/xA+I/fhaekwevrCcRa/WCV1s4I3VGahknPkyNJ8=; b=A810gJ8GWO9JLhgelYpMe4TFBMIXycWgLfaVkfbkrCaTrhQyLYDXyGKqEYi8kAoorq cem9TmtMm1kAJpudc2v48wVUDX0URGUmSrceRicZ6S5+lhwS3NmeqM6dW/CWgqaYzVl+ rrdaVd8vNUpg0Dm2LN9ltsyau6kQbSdhChOFM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=P4e/xA+I/fhaekwevrCcRa/WCV1s4I3VGahknPkyNJ8=; b=AzsCTrySe3mfod9Ucfmsj2PnfE9HX0FVu4BVqwf6sDQn04aC2KEiANnxzKxCI29KRr CLMk2dvfrwIrZZiYNsytjU1Re4i2Nd+mbdYdyMC8mu06AvGKEXHAyMsinhd1751JSOoj eoXDG2g927RCS7pkspvT5fucHGXinSF+JAKTZ5WVdMGuuRuRvipaOvR1SNZ5gnI6Osx0 u/ylif4nMPlywfdXNvjF6mDb4wtG+f9X6ciq3/36FZcpc7qshVqSw7SZh9UxKqCbHGJs 4pv/oBKeEscSQ9F4txHBwnbrJJs9HjPjLSkZSIJBaZkQhZ3sP70VqIse4+nblx78Wf2m iYlw== X-Gm-Message-State: APjAAAXbmpb6qi2TKwhjdjJai9/6RVIQ7bDw22/Cnn/vL9c5nujDjkkK /Ccf6fqFp8omL2ohvM9/fV+o5v4Snlk= X-Google-Smtp-Source: APXvYqztLw67egkehMcTC0D7aOOl7kCrsaIONdyJQbJTsWM2Ee6cU0j3VtnNtoIBnwoKKiPK9mYc7Q== X-Received: by 2002:a17:906:118b:: with SMTP id n11mr36452581eja.291.1558688074794; Fri, 24 May 2019 01:54:34 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:569e:0:3106:d637:d723:e855]) by smtp.gmail.com with ESMTPSA id 96sm567082edq.68.2019.05.24.01.54.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 May 2019 01:54:34 -0700 (PDT) From: Daniel Vetter To: LKML Cc: Intel Graphics Development , DRI Development , Daniel Vetter , Daniel Vetter , Bartlomiej Zolnierkiewicz , =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= , Peter Rosin , Hans de Goede , Mikulas Patocka , Rob Clark Subject: [PATCH 25/33] fbmem: pull fbcon_fb_blanked out of fb_blank Date: Fri, 24 May 2019 10:53:46 +0200 Message-Id: <20190524085354.27411-26-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190524085354.27411-1-daniel.vetter@ffwll.ch> References: <20190524085354.27411-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There's a callchain of: fbcon_fb_blaned -> do_(un)blank_screen -> consw->con_blank -> fbcon_blank -> fb_blank Things don't go horribly wrong because the BKL console_lock safes the day, but that's about it. And the seeming recursion is broken in 2 ways: - Starting from the fbdev ioctl we set FBINFO_MISC_USEREVENT, which tells the fbcon_blank code to not call fb_blank. This was required to not deadlock when recursing on the fb_notifier_chain mutex. - Starting from the con_blank hook we're getting saved by the console_blanked checks in do_blank/unblank_screen. Or at least that's my theory. Anyway, recursion isn't awesome, so let's stop it. Breaking the recursion avoids the need to be in the FBINFO_MISC_USEREVENT critical section, so lets move it out of that too. The astute reader will notice that fb_blank seems to require lock_fb_info(), which the fbcon code seems to ignore. I have no idea how to fix that problem, so let's keep ignoring it. v2: I forgot the sysfs blanking code. Signed-off-by: Daniel Vetter Cc: Daniel Vetter Cc: Bartlomiej Zolnierkiewicz Cc: "Michał Mirosław" Cc: Peter Rosin Cc: Hans de Goede Cc: Mikulas Patocka Cc: Rob Clark --- drivers/video/fbdev/core/fbmem.c | 4 +++- drivers/video/fbdev/core/fbsysfs.c | 8 ++++++-- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 9366fbe99a58..d6713dce9e31 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1068,7 +1068,6 @@ fb_blank(struct fb_info *info, int blank) event.data = ␣ early_ret = fb_notifier_call_chain(FB_EARLY_EVENT_BLANK, &event); - fbcon_fb_blanked(info, blank); if (info->fbops->fb_blank) ret = info->fbops->fb_blank(blank, info); @@ -1198,6 +1197,9 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd, info->flags |= FBINFO_MISC_USEREVENT; ret = fb_blank(info, arg); info->flags &= ~FBINFO_MISC_USEREVENT; + + /* might again call into fb_blank */ + fbcon_fb_blanked(info, arg); unlock_fb_info(info); console_unlock(); break; diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c index 5f329278e55f..252d4f52d2a5 100644 --- a/drivers/video/fbdev/core/fbsysfs.c +++ b/drivers/video/fbdev/core/fbsysfs.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -305,12 +306,15 @@ static ssize_t store_blank(struct device *device, { struct fb_info *fb_info = dev_get_drvdata(device); char *last = NULL; - int err; + int err, arg; + arg = simple_strtoul(buf, &last, 0); console_lock(); fb_info->flags |= FBINFO_MISC_USEREVENT; - err = fb_blank(fb_info, simple_strtoul(buf, &last, 0)); + err = fb_blank(fb_info, arg); fb_info->flags &= ~FBINFO_MISC_USEREVENT; + /* might again call into fb_blank */ + fbcon_fb_blanked(fb_info, arg); console_unlock(); if (err < 0) return err; -- 2.20.1