From owner-freebsd-stable@FreeBSD.ORG Mon Jan 28 02:28:19 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EDC7216A41A for ; Mon, 28 Jan 2008 02:28:19 +0000 (UTC) (envelope-from luigi@onelab2.iet.unipi.it) Received: from onelab2.iet.unipi.it (onelab2.iet.unipi.it [131.114.9.129]) by mx1.freebsd.org (Postfix) with ESMTP id B3D1B13C442 for ; Mon, 28 Jan 2008 02:28:19 +0000 (UTC) (envelope-from luigi@onelab2.iet.unipi.it) Received: by onelab2.iet.unipi.it (Postfix, from userid 275) id 42F927311C; Mon, 28 Jan 2008 03:12:02 +0100 (CET) Date: Mon, 28 Jan 2008 03:12:02 +0100 From: Luigi Rizzo To: "J.R. Oldroyd" Message-ID: <20080128021202.GA59612@onelab2.iet.unipi.it> References: <20080127205400.0a59507d@linwhf.opal.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080127205400.0a59507d@linwhf.opal.com> User-Agent: Mutt/1.4.2.3i Cc: Thomas Dickey , freebsd-stable@freebsd.org, eric@anholt.net Subject: Re: Low CPU Freq responsible for xterm pixel corruption on RELENG_7 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 28 Jan 2008 02:28:20 -0000 On Sun, Jan 27, 2008 at 08:54:00PM -0500, J.R. Oldroyd wrote: > Some weeks ago, I posted on the x11@ list of a problem of pixel corruption > I am seeing in xterm windows. An example of the problem can still be > seen here: > http://opal.com/jr/xterm-corruption.gif > Quick summary: Wide xterm windows (wider than 158 columns, 1440 pixels) > have the problem shown, but only when at least that many columns are on > the screen. That is, moving a wide window so that it is partially off > the screen causes the corruption to cease when less than 158 columns > are displayed. (trimmin thr Cc list) as a matter of fact i have been seeing the same problem also on RELENG_6, on a desktop PC without powerd, and using an Intel chipset with integrated video (i945 chipset) and the I810 driver: X Window System Version 7.2.0 Release Date: 22 January 2007 X Protocol Version 11, Revision 0, Release 7.2 Build Operating System: FreeBSD 6.2-STABLE i386 I seem to remember my laptop (Dell X300, i915 video card) also has similar problems with wide xterms. I believe the problem is in the i810 driver, or some interaction with the system (agpgart) rather than related to powerd and CPU freq. cheers luigi > Further investigation has unearthed that this problem happens only when > the CPU frequency is set to low levels, which was happening because of > powerd. When the CPU frequency is set low, these pixel corruptions happen. > When the CPU freq is raised they do not: everything is normal. > > Disabling powerd and manually adjusting the CPU frequency gives these results: > > # sysctl dev.cpu.0.freq_levels > dev.cpu.0.freq_levels: 3176/-1 2779/-1 2382/-1 1985/-1 1588/-1 1191/-1 794/-1 397/-1 > > CPU freq from 3176 to 1191 causes no problems. > CPU freq at 794 or 397 causes pixel corruptions. > > This problem did not happen on RELENG_6. > > -jr