PUC Serial I/O problem - copy of gnats-filed bug report (as discussed previously)

[Karl Denninger]

Karl Denninger wrote:
> This is pretty serious folks - as noted below I have tried several
> options including limiting FIFO depth with the flags with no result. 
> The PUC-based ports are basically useless under 8.x as a consequence.  I
> can reproduce this lockup within 15-30 minutes every time.
>
>   
>> Submitter-Id:  current-users
>> Originator:    Karl Denninger
>> Organization:  Karls Sushi and Packet Smashers
>> Confidential:  no <FreeBSD PRs are public data>
>> Synopsis:      Serial I/O is terminally screwed under 8.x.
>> Severity:      serious
>> Priority:      high
>> Category:      i386
>> Class:         sw-bug
>> Release:       FreeBSD 8.0-STABLE i386
>> Environment:
>>     
> System: FreeBSD FS.denninger.net 8.0-STABLE FreeBSD 8.0-STABLE #3: Fri
> Nov 27 08
> :32:51 CST 2009 karl at FS.denninger.net:/usr/obj/usr/src/sys/KSD-SMP i386
>
> puc0: <Oxford Semiconductor OX16PCI954 UARTs> port
> 0x4060-0x407f,0x4040-0x405f m
> em 0x94503000-0x94503fff,0x94502000-0x94502fff irq 16 at device 0.0 on pci3
> puc0: [FILTER]
> uart2: <16550 or compatible> on puc0
> uart2: [FILTER]
> uart3: <16550 or compatible> on puc0
> uart3: [FILTER]
> uart4: <16550 or compatible> on puc0
> uart4: [FILTER]
> uart5: <16550 or compatible> on puc0
> uart5: [FILTER]
>
> puc0 at pci0:3:0:0:        class=0x070006 card=0x00001415 chip=0x950a1415
> rev=0x00
> hdr=0x00
>     bar   [10] = type I/O Port, range 32, base 0x4060, size 32, enabled
>     bar   [14] = type Memory, range 32, base 0x94503000, size 4096, enabled
>     bar   [18] = type I/O Port, range 32, base 0x4040, size 32, enabled
>     bar   [1c] = type Memory, range 32, base 0x94502000, size 4096, enabled
>     cap 01[40] = powerspec 1  supports D0 D2 D3  current D0
>
>
> #
> # SMP -- Generic kernel configuration file for FreeBSD/i386 SMP
> #        Use this for multi-processor machines
> #
> # $FreeBSD: src/sys/i386/conf/SMP,v 1.5.6.1 2005/09/18 03:37:58 scottl Exp $
>
> include GENERIC
>
> ident           KSD-SMP
>
> # To make an SMP kernel, the next line is needed
> #options        SMP                     # Symmetric MultiProcessor Kernel
> #
> # We also need the firewall, divert, and PPS_SYNC (for the GPS) options
> #
> options         IPFIREWALL
> options         IPDIVERT
> options         PPS_SYNC
>
> #
> # Rate-shaping requirements
> #
> options         DUMMYNET
> options         HZ=1000
>
> #options                SYSVSHM
>
> #
> # Local stuff
> #
> device          rp              # Comtrol Rocketport Board
> device          sound           # Generic sound card drivers
>
> #device         ubsa            # USB Serial Adapters
> #device         ucom
> #device         uftdi
> #device         uplcom
>
> device          umct
> device          puc
>
>
>   
>> Description:
>>     
>         Serial I/O fails with a lockup after a variable amount of time.
>         Modem-controlled ports are succeptible, especially those that
>         require tight adherence to that capability.
>
>         There is no reset possible without rebooting the machine.  Attempts
>         to "probe" the port by stopping the running process(es) and
>         re-initializing them fail.
>
>         This IDENTICAL board in the IDENTICAL machine was functioning
>         properly under 7.x over the space of about a year under extremely
>         heavy use.  As soon as 8.x-RC2 was loaded, and subsequently with the
>         released version (as seen above) it failed and has remained dead.
>   
>         The custom kernel with "PPS_SYNC" is present as one
>         of the ports (on the motherboard) is used for a GPS clock under
> ntpd.
>         This port is operating fine - it is relatively low-traffic, of
>         course, containing only timecode.  Another port used to talk to an
>         APC UPS (again, low traffic) is also ok.
>
>         All ports in use for Hylafax, however, lock up as described above.
>
>         Attempting to limit FIFO depth with 0x100 or 0x200 flags on the    
>         ports has no effect.
>
>   
>> How-To-Repeat:
>>     
>         Put a "puc" style board in the machine, set up hylafax, send a few
>         dozen faxes.  The driver will wedge.
>
>   
>> Fix:
>>     
>
>         <how to correct or work around the problem, if known (multiple
> lines)>
>   
For what its worth, USB-based serial adapters also fail in the same way,
but faster (they have NEVER been reliable in this regard, and this
hasn't improved)

-- Karl