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 6CDCAC04AAF for ; Mon, 20 May 2019 08:23:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 399D120863 for ; Mon, 20 May 2019 08:23:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="BiYU87eY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731558AbfETIX3 (ORCPT ); Mon, 20 May 2019 04:23:29 -0400 Received: from mail-ed1-f66.google.com ([209.85.208.66]:45692 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731396AbfETIWy (ORCPT ); Mon, 20 May 2019 04:22:54 -0400 Received: by mail-ed1-f66.google.com with SMTP id g57so22487884edc.12 for ; Mon, 20 May 2019 01:22:53 -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=CumxJ2NtVSEP5RNMzgMskkfGKnWkqYH9OWapQsg3Ykk=; b=BiYU87eY751NVue2WirSevA+JtWzXlDUBKxpdvOCuE9SFAZutDfx84Zsh7QinEw1+x /YP4ChXJX2Hz4luhn5VXlZYJ8A5mSJGredVJzSCu87xqgKtLxkmTzP1VmxfyzsBTNq8N ff45HA03UxQVhL9TWuRtiTxSXr2xq30e/D90Q= 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=CumxJ2NtVSEP5RNMzgMskkfGKnWkqYH9OWapQsg3Ykk=; b=gxqvZJY8QvBZmhSZZMu2ndCEn/WpmeFE55TQNsm63iBPGGWrrHuhW4XgS8HJB7IjfL T3RHFz1QXkVR8U5W+AW+62iTqoWxtO3pkbfzlR1O6zjX5N66Ux3sK0hbemhu/J+SHMtt wYY0OCvt+e/qm5nPcXvYlYQj1qKUbIId23wgdfAixUWPYi28TxulLkQJgelNjEhlp7Ul pNw7lP+2bBzqWAZYk7yzWQs2a5J4ZBw9FP7NMr0kjXv3QwH2Rw1Y9u4U2RmtPZ7AzAYU QRtSkMcrmsU7F/bBptq0JgUvzDKAlWLXLtq4zgCd+bM3Si15ZszD3ieE8kXwlLqVkkXs U25w== X-Gm-Message-State: APjAAAUKnO0C5xPbEIH/EmvbJNFIEMpNJv6H/rPNANTPYKmTF4yEJO4r JG5WJg2VjQHaJXsPeeuJgHWR8Q== X-Google-Smtp-Source: APXvYqzKocCCpdIn3BgvIXkZbMH0Ck4pkHA663Xdj8pJGjwyoQ9kIknubmApc8RiuGcyohuJzMWALQ== X-Received: by 2002:a17:906:af57:: with SMTP id ly23mr26150862ejb.98.1558340572842; Mon, 20 May 2019 01:22:52 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:569e:0:3106:d637:d723:e855]) by smtp.gmail.com with ESMTPSA id t25sm3021263ejx.8.2019.05.20.01.22.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 May 2019 01:22:52 -0700 (PDT) From: Daniel Vetter To: DRI Development Cc: Intel Graphics Development , LKML , 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 26/33] fbmem: pull fbcon_fb_blanked out of fb_blank Date: Mon, 20 May 2019 10:22:09 +0200 Message-Id: <20190520082216.26273-27-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190520082216.26273-1-daniel.vetter@ffwll.ch> References: <20190520082216.26273-1-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 9932130bf728..7f95c7e80155 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