Mac Pro - Mac Pro keeps crashing when using with KVM. where to start my investigation?
hi guys.
i have recently ordered ATEN CS-1762 KVM switch (2 ports model) to control my Mac and PC with a single keyboard and mouse. This KVM supports USB and DVI. the problem i have is Mac crashing when i switch from PC. I contacted mfg lately and they are unaware of this issue due to not having Mac Pro to test with this appliance. They have tested it with Mac Mini, G4 and G5 though and all was OK. based on this they put a description that this box is compatible with Mac. Anyway, being relatively new Mac user i ask for your help.
here are my steps and some ATEN's thoughts:
1. accroding to ATEN tech support, i should power up my second computer after the first one was started and is running. firstly i start the Mac Pro, 5 mins after that i power up my PC.
2. When both computers are up and running (Mac is in KVM focus), i switch to PC and all seems OK. I have noticed though that if NumLock is activated during the PC session, I won't be able to switch back to Mac. However, even though NumLock is OFF i still may have troubles when switching back to Mac. So it is not the rule, but maybe the clue to start with..
NOTES:
1. if i start PC first, Mac won't start at all. The power led will be on, but there will be no picture on the monitor and it won't accept any keyboard/mouse inputs as well as it will be network inaccessible.
2. I tried looking into Mac's logs but need your help in getting this clear.
here is the log. as you will see it stops at 13:04 and then continues at 13:08 after reboot.
i've seen some parallel's VMs but i don't have Parallels installed. i used to have it, but then it never happened to work so i deleted it from the machine. can this be the case it is still somewhere?
pls guys, any thoughts are very welcome!!!
PS: i can cause Mac to crash the same way if necessary or if log looks inclomplete. the thing forgot to mention is: when Mac crashes and i reboot it, it will not necessarily boot up completely. i've noticed that i would have to reset the KVM switch prior to Mac's successful start up. so maybe i copied the wrong log (not the one immediately after the crash). pls advise here
Alex
EDIT: specs for machines are:
Mac Pro dual 2.6GHz, 1GB (+1GB aftermarket added half a year back, works perfectly), HDD 260GB, Nvidia 7300 256Mb.
PC - Supermicro dual xeon 1.6GHz, 4GB Ram, 4 x 36GB SCSI, Nvidia 5200 256 MB with Windows 2000 Server.
ok so i experimented a little with the hardware and here what i have to the moment:
1. i thought that the usb kb could be the case for mac os to crash so i disconnected the cable from the KVM and plugged normal apple kb to the mac.
2. however when i tried switching back to mac, the machine crashed again.
from what i noticed for the last few days 'working' with this kvm switch was the screen resolution changing while i was switching. meaning the screen flickered for couple of times prior to showing 1280x1024 that was set up in the system. during flickering the resoution became 1024x768. i 've seen it pretty clearly, just it was for half of a second.
also when powering up both machines, they were starting with 1024x768 and not 1280x1024 as was set up. i had to manually change the screen resolution on both machines (pc and mac) every time after successful start up.
so by far my understanding is that kvm switch forces monitor for 1024x768 during switches and on start up. it also causes the OSes (win2K and MacOSX) to lose 1280x1024 and accept 1024x768 as if the monitor was changed and couldn't operate at a higher resolution.
having said that i uploaded this info to kvm mfg (ATEN) and couple more mac forums so that this info may help someone else when ordering a kvm for mac. at the same time i am still open for any thoughts, advices and crazy ideas to get round this bug.
good stuff!!! i finally have this piece of kit working with my mac pro!
many thanks to Dale @ kvmchoice.com tech support for the brilliant idea to increase the scan interval from 5 secs (default) to 20 (out of 99 possible). it seems like kvm hasn't had enough time to "ping" the video card (nvidia 7300) and read the resolution settings every time i moved the focus to mac pro. being unable to get this data kvm simply forced the video card to switch to kvm's default 1024x768.. this caused mac pro to crash with graphics error in the panic log.
well, i am still testing the system, but by far i switch back and forth without any problems whatsoever and it makes me very happy!!
good luck to all and don't forget to check the scan interval when using your dvi/usb kvm with the mac pro!
changing the scan interval didn't help. after a few days the problem happened again and was occuring ever since.
manufacturer was out of help. seems like they cannot afford to buy Mac Pro to complete the testings or maybe they are simply not interested in porting it to new Macs or anything else.
i had to return this kvm back as it proved to be useless with Mac Pro. so far it did more harm to it.
That's too bad. I'm having the exact same problem with the Aten 1762 and a Mac Pro. After finding your post, I changed the interval and it worked for about a day and a half for me before the Mac Pro crashed again. Looks like I'll have to do the same and give up on this product. Thanks for all the information you have posted. Other than your info, there's not much out there about this problem!
Mac Pro - Mac Pro keeps crashing when using with KVM. where to start my investigation?
