Jean-Luc Pamart wrote: > Jan Kiszka a écrit : >> Jean-Luc Pamart wrote: >> >>> Hello >>> >>> I am a newbie with Xeno. My goal for the beginning of 2007 is to launch >>> a project for 4 french studiants : a box with Linux embedded and a usb >>> camera. The embedded application will analyse the movies in Real time >>> and lead a mobile machine with CAN-BUS. >>> Now i play with Xeno for my knowledge (without specific hardware) : a >>> little linux installed in a usb key with a little embedded distrib >>> >>> - vanilla kernel 2.6.16 with patch for usb [.config is joint] >>> - Xenomai 2.1.2 >>> - essentially BusyBox >>> - for xenomai : only "latency" directory and libs in usr/libs >>> I have checked "SMI woraround" for the kernel. >>> In BIOS I have UNchecked "legacy usb". >>> >>> >>> my Desktop PC (a AMD ATHLON) can boot with this little vanilla kernel >>> and >>> 1/ a little embedded distrib of my own >>> >>> OR >>> >>> 2/ a complete mandrake 9.1 on a partition of a classic hard disk >>> >>> I have 2 differents problems when I lauch this : >>> >>> 1/ with the linux embedded directories on the usb key >>> high latency > 100 us are ok ? perhaps usb work is not compatible >>> with RT ? >>> >> >> Try loading the standard USB drivers (at least uhci_hcd) if they aren't >> yet. Actually, I've seen boxes (granted, they were far older) where I >> had to switch legacy USB *on* to avoid disturbances. In any case, check >> carefully if you followed all tips in TROUBLESHOOTING regarding latency >> issues (APM, ACPI, etc.). >> >> >>> 2/ with the complete mandrake 9.1 : >>> it crashes X after 1 or few minutes. >>> What is the relation between X and Xenomai ? >>> Is Xenomai compatible with X ? >>> >> >> Yes, as long as X is not playing against us, e.g. by hard-disabling >> interrupts or doing (too) evil things on the buses. Any non-GPL driver >> in this game here (NVidia&Co)? Better avoid this. Also try to disable >> accelerated mode in your X setup to see if things improve. >> >> Jan >> >> > Ok , for the box with a vanilla kernel I will try the differents > possibilities. Actually i disable > a max of things ... > > For the box with X : the big surprise was : very goods latencies > (comparativeley with no X !!) > Why ???? > (Before crashing)
If it turns out to be an ACPI/APM issue, X may keep your box busier than plain text mode, thus avoid those latency peaks by keeping it out of certain sleep modes - well, an attempt to explain something I can't with the currently available information... > > for crashing > I 'll verify theses 2 points : > nvidia driver > accelerated mode : Is it a x server setup ? > See Gilles' reply => XF86Config. Jan PS: Don't forget to reply-to-all.
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