Date: Fri, 14 Mar 2008 12:59:23 +0100 From: Tijl Coosemans <tijl@ulyssis.org> To: Reid Linnemann <lreid@a.cs.okstate.edu> Cc: freebsd-questions@freebsd.org Subject: Re: DRI on radeon 9500 using too wide memory bus? Message-ID: <200803141259.25941.tijl@ulyssis.org> In-Reply-To: <47D9A07F.5040108@cs.okstate.edu> References: <47D8C274.5030107@cs.okstate.edu> <47D9A07F.5040108@cs.okstate.edu>
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On Thursday 13 March 2008 22:45:35 Reid Linnemann wrote: > Written by Reid Linnemann on 03/13/08 00:58>> >> I've had DRI running on a radeon 9500 for a while now, and at some >> point in time tracking 6-STABLE and continuing now on 7-STABLE I've >> started seeing rendering artifacts in gl in the form of a >> cross-hatch pattern of pixels that don't get filled. At first I >> figured the card was failing, but I remembered a fact about the 9500 >> that made me doublethink that. >> >> The radeon 9500 is an r300 chipset, and differs from the 9700 only >> in the width of the memory bus (128 bit vs 256 bit) and possibly >> clock speed. If memory serves, the chip itself had the capacity to >> address 256 bits, but most 9500s just went out the door with 128 bit >> memory. I remember at one point in time trying out a hack to the >> 9500 driver that enabled the 256 bit bus to see if I had a rebadged >> 9700, and had similar artifacts. >> >> So I decided to peruse my X logs, and sure enough I see: >> (--) RADEON(0): Mapped VideoRAM: 131072 kByte (256 bit DDR SDRAM) >> >> Is it possible that the radeon driver is using the 256 bus? Is there >> a way to force it to use a 128 bit bus? Has anyone else seen this? > > On further investigation, I tried forcing the driver to switch to a > 128 bit bus by setting the R300_MEM_NUM_CHANNELS_MASK bits on > RADEON_MEM_CNTL to 0x1, but the problem did not go away. > > I'll try describing it a little better.. only with gl acceleration, > the entire gl context appears to have criss-crossing lines 4 pixels > wide that are randomly filled correctly or black, so that they form > roughly a chain link fence pattern of trash on the gl context. Anyone > have an idea? I can't help you with this, but I'm thinking you'll have a higher chance getting an answer on some DRI/DRM mailinglist. You could also ask the port maintainers (x11@). Some of them are also active developers on DRI, and the r300 driver, or at least used to be in the past.home | help
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