Date: Sat, 7 Mar 2009 09:57:08 -0500 From: Justin Hibbits <jrh29@alumni.cwru.edu> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: Peter Grehan <grehan@freebsd.org>, freebsd-ppc@freebsd.org Subject: Re: graphics on G4 Message-ID: <20090307145708.GA1128@narn.knownspace> In-Reply-To: <20090306120626.GA12461@narn.knownspace> References: <20090304091310.EQW86822@dommail.onthenet.com.au> <20090304215257.GA8306@narn.knownspace> <49AF223C.5010907@freebsd.org> <20090305125438.GB8306@narn.knownspace> <49B0712B.1090109@freebsd.org> <20090306120626.GA12461@narn.knownspace>
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This is a MIME-formatted message. If you see this text it means that your E-mail software does not support MIME-formatted messages. --=_beta-6284-1236437795-0001-2 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline On Fri, Mar 06, 2009 at 07:06:26AM -0500, Justin Hibbits wrote: > > >> Did you ever discover whether writing to random bits of the framebuffer > > >> without ever having run X also causes this problem? > > >> -Nathan > > > > > > Yes, I did perform that test, and it does cause the problem as well. For me it > > > hangs when starting a new process some time later, so can be tested somewhat > > > easily by performing a buildworld after doing the graphics test. > > > > My card, at least, has a framebuffer BAR that is 128 MB long, but only > > actually has 32 MB of graphics RAM. Writing anything to that 32 MB does > > not cause problems, but of course writing beyond that kills the machine, > > since that memory region does not actually exist. Is this true for yours > > as well? > > -Nathan > > My card has 256MB of graphics RAM, and according to dmesg allocates that size > block, plus 64k in the 256MB region before it. I haven't yet tested what > address byte actually causes the crash, but that can be determined relatively > easily. What I'm guessing, though, is writing to anything past (end - 32k) will > cause the crash. I'll see if I can test this weekend. > > So, short answer to your question: it's not quite true for me, because it > happens when I write to what should be inside graphics RAM. > > - Justin Nathan- Attached is a simple program I wrote that just writes a straight line down the first column of the framebuffer. It reliably kills my system while running a 'make buildworld' within a few minutes of running this program. (Possibly) Relevant Details: ATI Radeon 9600PRO, 256MB edition. 1280x1024x8 framebuffer 1.25GiB RAM - Justin --=_beta-6284-1236437795-0001-2--
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