From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: What triggers a redisplay when no command or timer? Date: Thu, 07 Sep 2017 17:50:20 +0300 Message-ID: <83zia6zhoz.fsf@gnu.org> References: Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1504795906 14974 195.159.176.226 (7 Sep 2017 14:51:46 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 7 Sep 2017 14:51:46 +0000 (UTC) Cc: emacs-devel@gnu.org To: Keith David Bershatsky Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Sep 07 16:51:28 2017 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dpy96-0002Wy-GB for ged-emacs-devel@m.gmane.org; Thu, 07 Sep 2017 16:51:08 +0200 Original-Received: from localhost ([::1]:40798 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpy9D-0005c8-LE for ged-emacs-devel@m.gmane.org; Thu, 07 Sep 2017 10:51:15 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35798) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpy8T-0005bt-5n for emacs-devel@gnu.org; Thu, 07 Sep 2017 10:50:33 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dpy8J-0007lu-D8 for emacs-devel@gnu.org; Thu, 07 Sep 2017 10:50:29 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:58919) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpy8J-0007lm-AJ; Thu, 07 Sep 2017 10:50:19 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:1901 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1dpy8I-0000kf-Ck; Thu, 07 Sep 2017 10:50:19 -0400 In-reply-to: (message from Keith David Bershatsky on Wed, 06 Sep 2017 21:57:26 -0700) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:217978 Archived-At: > Date: Wed, 06 Sep 2017 21:57:26 -0700 > From: Keith David Bershatsky > > I would like to insert a GLYPH_DEBUG message into xdisp.c to let me know that "UNKNOWN" triggered a redisplay when there is no command and/or timer function at issue. > > Step 1: On OSX (and maybe other Emacs OS builds), start GUI version of master branch built with Glyph Debug support. > > Step 2: Turn off blink-cursor-mode. > > Step 3: Remove the jit-lock timer function with (setq timer-idle-list nil) > > Step 4: Check the timer-list and timer-idle-list to ensure they are nil. > > Step 5: M-x trace-redisplay > > Step 6: Wait 1 to 2 minutes and watch how a redisplay is triggered with nothing more helpful than a singular `redisplay_internal 0` message. > > I would also like to please understand what this "UNKNOWN" event is and where it comes from. I don't see here what you describe. Emacs is sitting doing nothing and not entering redisplay, if I take care not to move the mouse and/or having the Emacs frame have focus. But you don't need us to answer your question: just run Emacs under a debugger, put a breakpoint in redisplay_internal, and when it breaks, look at the backtrace. If you cannot figure out what you see, post the backtrace here. In general any event provided by any input source, including messages from the window-system, could potentially cause what you describe. Note that the trace message you are citing means just that Emacs entered redisplay, but it doesn't mean something will actually be redisplayed, because redisplay_internal could return right away under some conditions.