I haven't seen this problem, but it appears to be order related and that's probably why I missed it.
I think the right answer is to move the call to uart_register_ldrv() out of uart_configure_port() and move it into uart_add_one_port() after the mutex->state is unlocked. However, I haven't tested it. If that works, could you send a patch? I'm currently completely reworking this, as the kernel developers didn't like the approach. Thanks, -corey David Jenkins wrote: > Hi, > > I am setting up IPMI for an ATCA board with a pigeon point MMC on it. > This requires the serial driver. I have downloaded the 2.6.18 serial > patches and applied them. There seems to be a problem with some > mutex_lock(&state->mutex) code in the layered driver interface added > to serial_core.c > > In particular in the uart_register_ldrv() function there are two > places where the mutex's don't jive > a) a mutex_lock(&state->mutex) is done when a lock of this mutex is > still in effect from two layers up (mutex locked in > uart_add_one_port() that calls uart_configure_port() that calls > uart_register_ldrv(). > > b) the call to uart_ldrv_open() assumes that the state->mutex is > unlocked - but again it has been locked two layers up in > uart_add_one_port(). > > I went back and checked that my 2.6.18 serial_core.c is valid - > certainly appears to be. I did notice that between 2.6.16 and 2.6.17 > locking/unlocking state->mutex was added to uart_add_one_port(). > Taking the lock/unlock out at this level does remove the contention > but doesn't seem advisable. > > Problem a) can be fixed easily as the lock/unlock isn't needed locally > in uart_register_ldrv() when it is already locked. Problem b) isn't > as easy to resolve. I noticed that elsewhere a unlock is done before > a call to uart_ldrv_open(). My current solution is to also wrap the > call of uart_ldrv_open() in uart_register_ldrv() with unlock/lock. > > Has the issue been resolved elsewhere already? I browsed the CVS > repository and didn't see any updates. > > Thanks > > David Jenkins > > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > ------------------------------------------------------------------------ > > _______________________________________________ > Openipmi-developer mailing list > Openipmi-developer@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/openipmi-developer > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Openipmi-developer mailing list Openipmi-developer@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openipmi-developer
