After reading somw of the documentation/white papers about rtlinux I came up with a question. As I understand it, rtlinux emulated interrupt hardware for the non-rt linux kernel, so that when the non-rt kernel disables interrupts they aren't actually disabled but rather the rt kernel just queues them until they are reenabled. I was wondering how this would work for interrupts that are level sensitive, like PCI, and remain active until they are actually dealt with. Wouldn't this interrupt just keep coming in, causing the rt lernel to keep queueing it and cause a noticable performance impact? I'm sure I'm just missing a cruicial piece of the logic here, I'm just wondering what that piece is. Thanks in advance for any explanations you can provide. And a different topic. I am currently working on a project using qnx4.25 and photon 1.13 (www.qnx.com) that does realtime data acquisition using a busmastering PCI device, does some realtime processing on the data, and sends the data back out through the same PCI busmaster device (an AMCC 5533 if I'm remeberign correctly). What I'm wondering is 1) Has anyone had any experience porting QNX code to rtlinux, I know the message passing is basically available and that all the photon gui stuff will probably get thrown out, are there any other gotchas to be concerned about? 2) Has anyone used rtlinux to do PCI busmastering, seems like if you can't make system calls from realtime tasks that would include the pcibios_read_config* and pcibios_write_config* functions, making it hard to control the PCI device. Any advice would be apprecieated. John Carpenter software engineer embedded medical devices [EMAIL PROTECTED] http://www.ticon.net/~barak/linux.html --- [rtl] --- To unsubscribe: echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED] ---- For more information on Real-Time Linux see: http://www.rtlinux.org/~rtlinux/
