Running Gentoo and Slackware 64bits and getting bad system hangs from I/O (the exact same way on both OS's). Both installs share the same home folder.

With MAME, I get a series of hard-locks and system stalls every 45 seconds (HDD activity light blinks madly like the HDD is doing abunch of loading). This renders playing games completely pointless (I even bought the roms legally from MK Arcade Kollection). I'm also getting problems with TV-tuner capture card. When capturing lossless data (or even mpeg2 from the hardware encoder), dmesg get's spammed with buffer overflow error messages and captures result with dropped frames (really jerky and/or corrupt playback). It's as if I have an IRQ conflict.

Everything worked fine before, for the longest time before changing GPU vendors. I upgraded from an nvidia 9800GTX to an ati HD 7750, and noticed wireless adapter started losing packets and system would hang (when downloading as root from terminal framebuffer, wireless card would lock up computer when it dropped packets). When changing from the ati HD 7750 to the nvidia 8400gs, this is when I got the worse system hangs (as they are right now).

8400gs also has a dumb problem where everything is scaled to a different resolution (it used a different monitor before I switched to my current one, and it thinks I'm still using the old one); this makes all resolutions look horrid since it doesn't let my display do the scaling. So I figure it's something lame with the 8400gs firmware.

Tried flashing the 8400gs firmware-bios to alleviate its stubborn resolution scaling (it does it from POST and even with vesa modes). But this caused an I/O error on /dev/nvidia0, preventing Xorg from starting (startx). Flashing 8400gs back to its original firmware brought Xorg back to working, but I still have dreaded system hangs (the stupid GPU scaling didn't change anyway)...

Removed my capture card, moved 8400gs to different pcie slot, unplugged keyboard, switched usb ports, disabled sound card firewire and serial ports, deleted ~/.nvidia-settings.rc, but same problem.

Under Windows everything works fine. No hangs with MAME, capture card seems very responsive, no slowdowns. I'm almost positive FGLRX drivers are to blame.

I did `sh /usr/share/ati/fglrx-uninstall.sh --force ; rmmod fglrx ; ldconfig` under both Slackware and Gentoo (did `emerge --unmerge ati-drivers ; rmmod fglrx ; merge nvidia-drivers ; eselect opengl set nvidia ; ldconfig ; . /etc/profile ; env-update` under gentoo).

So did the FGLRX drivers do something, or does Linux not handle IRQ's as good as Windows?

Regards

1. Try this:Apart from the symlinks, you may see any or all of

ligGL*.so.1.2 #Mesa & OSS driver version
libGL*.so.<ati driver version> # ATI binary blob version
libGL*.so.<nvidia driver version> # Nvidia binary blob version

Make sure your symlinks point at the correct one for the driver you now have. Repeat for 32 bit stuff.

2. I would suggest updating - libdrm, X server, mesa and pixman. With so much driver swapping, you may be in a mess. Even reinstall & overwrite if there is no new versions. Ditto for 32 bit stuff.

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Upon further testing I found Windows has about 50ms input lag (xbox 360 controller) in MAME. Linux, despite using 300hz timer, has 0 lag (everything's instant despite hangs every 45 seconds). I'm guessing something is wrong with PCI latency but this is by far the worst case I've had. Guess I really do need to buy a video card (have two PCIE16x slots and problem persists in either one with 8400gs). Linux seems better at showing these flaws rather than hiding them like Windows maybe (which is good IMO)...

As a note I'm using the 8400gs with newer core (less shaders vs old one).

Going to purchase new card (going to have to sell laptop=arrrrgh) and hopefully problems will go away. Want to go NVIDIA but lack of open source support and this experience leaves a disturbing taste in my mouth. Nvidia binary drivers do support custom modelines just fine which is a must for MAME, whereas I need to hack an EDID file with custom modelines for FGLRX (400x254@109hz on CRT is a must for Mortal Kombat games; you get crisp display with natural hardware scanlines and rock solid vsync with 0 lag. Way better than MK Arcade Kollection frontend with typical interpolation scaling).

On PCI latency: Instant is impossible; Dead fast is possible. I don't know how you measure 50ms, as I would consider that pretty instant. I would expect windows to throw up equally complicated graphics faster than wine/linux, but it's quite possible linux uses a simpler graphics.

Having things faster and hanging every 45 seconds is weird in the extreme - it's an oxymoron, actually. How long does it hang for? Are you sure that's not your latency?

If I were trying to do what you are trying to do (Thank goodness I'm not , I would set up one distro for ATI, and one for Nvidia, and swap cards or the like.

/In a moment of reversing himself
if the games are priority number 1, and
if you can swallow pride, and
if you have the cash for a new video card of substance and
if you are not a purist, and
if you are prepared to be a traitor and ...(etc.)

Try a windows version instead of the new video card. I always felt certain things were done better in windows, and being windows is one of them; graphics is another.

Ideally grab a beta or trial version if you can, because the idea is probably madness, and you will find that out quickly. It would be a shame to have parted for money to find that out (again)

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Problem solved. Turns out it was me causing it (except the input lag in windows; okay maybe that's my fault too hehe). Was telling MAME to record gameplay and write MNG, AVI, and WAV files in the ini file. Disabling that solved the problem. Still get buffer overflow errors when capturing but that's expected. Now I have to hope the store cancels my order before shipping. Many thanks for all the tips!