Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751743Ab0HPCvy (ORCPT ); Sun, 15 Aug 2010 22:51:54 -0400 Received: from smtp-out-249.synserver.de ([212.40.180.249]:1031 "EHLO smtp-out-244.synserver.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751185Ab0HPCvx (ORCPT ); Sun, 15 Aug 2010 22:51:53 -0400 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: markus@trippelsdorf.de X-SynServer-PPID: 11404 Date: Mon, 16 Aug 2010 04:51:46 +0200 From: Markus Trippelsdorf To: Linus Torvalds Cc: Dave Airlie , Chris Wilson , Zhao Yakui , Jesse Barnes , Adam Jackson , DRI mailing list , linux-kernel@vger.kernel.org Subject: Re: Intel graphics CPU usage - SDVO detect bogosity? Message-ID: <20100816025146.GA1639@arch.tripp.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1525 Lines: 36 On Sun, Aug 15, 2010 at 07:32:15PM -0700, Linus Torvalds wrote: > I started wondering why 'top' was showing an otherwise idle system as > having a load average of 0.5+, and worker threads constantly using the > CPU. > > So I did a system-wide profile, and got the attached output (look at > it in a really wide terminal). > > There seems to be something _seriously_ wrong with i915 SDVO detect. > This is on an Apple Mac Mini (hey, your favorite problem child!), and > apparently it spends 20% of its non-idle CPU time just doing udelay's > for the i2c SDVO connection detection. > > That sounds a bit wrong, doesn't it? > > I don't know how recent this is - it might have been going on for some > time without me noticing. It's the wife's computer, and the same thing > doesn't seem to happen on my Core i5 desktop > > Any ideas? Any information I can give about the machine? You're not alone. I'm seeing similar things on my machine (AMD,Radeon). The monitor outputs are polled every 10 sec in drivers/gpu/drm/drm_crtc_helper.c. There is a patch attached to the following bug report that disables polling and solves the problem for me: http://bugs.freedesktop.org/show_bug.cgi?id=29536 -- ?A man who doesn't know he is in prison can never escape.? William S. Burroughs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/