Date: 10 Feb 1998 13:01 EST From: "Andrew Atrens" <atrens@nortel.ca> To: hackers@FreeBSD.ORG Subject: pci-ide-dma side effects Message-ID: <199802101859.KAA19606@hub.freebsd.org>
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Hi All, I'm running "1/30/98 - current", on an AMD-K6/200 w. ASUS TP97 mobo. Last night curiousity got the best of me, and I was tempted to try out the wd driver's DMA support. To do this I changed my kernel config from: controller wdc0 at isa? port "IO_WD1" bio irq 14 flags 0x80ff80ff vector wdintr to: controller wdc0 at isa? port "IO_WD1" bio irq 14 flags 0xa0ffa0ff vector wdintr To make a long story short, I launched the new kernel, DMA *was* detected: Probing for devices on PCI bus 0: chip0: <Intel 82439TX System Controller (MTXC)> rev 0x01 on pci0.0.0 chip1: <Intel 82371AB PCI to ISA bridge> rev 0x01 on pci0.1.0 ide_pci0: <Intel PIIX4 Bus-master IDE controller> rev 0x01 on pci0.1.1 chip2: <Intel 82371AB USB host controller> rev 0x01 int d irq 255 on pci0.1.2 chip3: <Intel 82371AB power management> rev 0x01 on pci0.1.3 vga0: <ATI Mach64-GX graphics accelerator> rev 0x03 on pci0.9.0 wdc0 at 0x1f0-0x1f7 irq 14 flags 0xa0ffa0ff on isa wdc0: unit 0 (wd0): <ST52520A>, DMA, 32-bit, multi-block-16 wd0: 2446MB (5009760 sectors), 4970 cyls, 16 heads, 63 S/T, 512 B/S launched X, then ran `Bonnie'. What happened next is hard to describe. :) My X screen was filled with (for want of a better description) `marching ants'. It was as though the screen was `swimming'. I suspended `Bonnie' and the swimming stopped. :) Lots of garbage on the screen, so I did a screen refresh and everything went back to normal. I resumed `Bonnie' and swimming started again on cue. Then my monitor appeared to lose the graphics card sync signal and began behaving very strangely, then it went into power-save mode and shut down. I re-suspended `Bonnie', did some CTRL-ALT-F? things and back it came! I killed and re-started Bonnie again, quickly switched to a cons screen, started `top' and waited for Bonnie to complete. I then unmounted and fsck'd the filesystem - it was clean as a whistle! And so ended the experiment. Needless to say, I've backed away from ide DMA for now. :) Comments? Have I done something glaringly stupid here to expect this result? :) (The purpose of this post, actually, is to provide some feedback to the IDE DMA folks - to hopefully help them find a bugster, if one exists. I am willing to be a guinea pig if someone requires more data about this anomoly. If hackers is the wrong forum for such a post please let me know so that I may correctly address future sightings. ) No flames please. Andrew. (opinions mine, not Nortel's) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe hackers" in the body of the message
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