You are completly right! The fact that the old kernel worked "by chance" with a wrong-setup due to the buggy behaviour you comment and that the new one got the correct setup after rmmod/insmod again "by chance" put me in the wrong direction. You saved me from future random errors and a lot of headaches! Thanks a lot! Enrique On Fri, Dec 10, 2010 at 5:22 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 10 Dec 2010, ENRIQUE ARIZON BENITO wrote: > >> Yes, I did. In fact the setting as displayed from the output command >> "stty -a -F /dev/ttyUSB0" are equals both for the working kernel and >> the new (non working) one. > > That means nothing, since the kernel's behavior in this regard has > changed. ÂOlder versions of the kernel were buggy; they would not block > for a handshaking signal when they should have. ÂThat's probably why > your test didn't hang under the working kernel. > > To prevent waiting for a handshake signal, you can do > > Â Â Â Âstty -F /dev/ttyUSB0 clocal -crtscts > > before running the test. ÂBut a better idea is to avoid doing regular > I/O to a serial port and instead use a program designed for that task, > like minicom. > > On Fri, 10 Dec 2010, ENRIQUE ARIZON BENITO wrote: > >> Solved! >> >> Udev was loading both uhci an ohci even if the system was not using ohci at all. > > That would not cause any problems. ÂThe ohci-hcd driver would simply be > inactive; it would not interfere with uhci-hcd. > >> Â"rmmoding" both on them as well as "pl2303" and "modprobing" uchi and >> pl2303 (in that order), the blocking dissapeared. > > I think you are fooling yourself. ÂThe port settings are much more > likely to be the cause of the problem. ÂReloading pl2303 probably > caused the settings to change. > >> ohci was also beeing loaded by the old 2.6.30 kernel. Still it didn't >> affect the normal behaviour. That makes me suspect there could be >> another bug somewhere else. > > Not a bug, just the system operating the way it is supposed to. > > Alan Stern > > > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
