#linuxcnc-devel Logs

Feb 12 2018

09:11 AM jepler: the new ioctl-based gpio interface still may not be high performance. It's possible for one ioctl() to read multiple values or write multiple values, but I think you can't mix reads and writes within a single request, so "byte-banging" would still be multiple ioctls per byte (e.g., set output data, strobe clock, read input data = 3 ioctls)
09:13 AM jepler: for literal gpio it's probably not bad, you could do all the reads (up to 64) in 1 ioctl and then all the writes in a second ioctl
09:20 AM jepler: .. there's probably a forum reboot coming soon, but out of my control, as DigitalOcean reboots their hypervisors with spectre & meltdown mitigations
09:20 AM jepler: you might say: they didn't do that a month ago !?
09:20 AM jepler: ikr
09:24 AM jepler: https://blog.digitalocean.com/a-message-about-intel-security-findings/ they're working on NYC1 right now, forum is in NYC2
09:29 AM rene-dev: jepler does that not also depend on bank mapping? I think a single ioctl can only control one bank at a time
09:30 AM rene-dev: but yes, you will need multiple to transfer stuff...