[hcflinux] only root can access /dev/ttySHCF0 first time after reboot

[Richard Leonard]

I have a strange problem. My Conexant HCFPCI modem works well, except that after each reboot, I must connect as root the first time I try. Thereafter my normal user account works OK. 

I connect using the pon script, which leaving out a few options is basically: exec /usr/sbin/pppd call ${@:-provider}. Running this as a normal user first time after reboot causes pppd to give the error "Failed to open /dev/ttySHCF0: No such device". Same result from user doing a /usr/sbin/pppd call provider. The device is right there, and root can use pon to connect through it just fine.

Oddly, I tried using another front end to pppd, and kppp connects perfectly when run as a normal user, but I'm trying to avoid kde on this slowish box. 


Details:
Libranet 2.8 (libranet's gui dialer, lppp, has the same problem as pon)
Installed the generic tarball (hcfpcimodem-0.99lnxtbeta03042700) a couple of months back, which compiled fine and ran hcfpciconfig without difficulty. Device IDs and so on are the same as on the Mandrake 9.1 installation on this box, when I used the rpm to install.

crw-r--r--    1 root     root     240,  64 Sep 19 08:00 /dev/ttySHCF0
-rwsr-x---    1 root     dip        481336 Mar 18  2003 /usr/bin/kppp
-rwxr-xr-x    1 root     root          956 Nov 24  2002 /usr/bin/pon
-rwsr-xr--    1 root     dip        234504 Nov 24  2002 /usr/sbin/pppd

I'm a member of dip. Changing the owner and/or group of /dev/ttySHCF0 to dip makes no difference.

I've searched the list archives, googled, read man pages, changed permissions, groups and memberships every way I can think of, and have got nowhere. I simply can't work out why running pon as root works, or running kppp as a normal user works, when the suid bit on pppd should have the same effect. If need be I can keep kppp around, but would prefer not to have to. All advice now received with deep gratitude, and apologies if there is something obvious I have missed.

Thanks in advance
Richard