Re: lpt stopped working

From: John Baldwin <jhb_at_freebsd.org>
Date: Tue, 10 Feb 2009 16:12:57 -0500
On Tuesday 10 February 2009 3:14:47 pm Alexey Shuvaev wrote:
> On Mon, Feb 09, 2009 at 02:58:41PM -0500, John Baldwin wrote:
> > On Monday 09 February 2009 1:58:39 pm Christian Gusenbauer wrote:
> > > On Monday 09 February 2009, John Baldwin wrote:
> > > >
> > > > Please help to debug this so we can have working lpt0 in 8.0.  No one
> > > > tested the patches months ago when I first posted them, and if folks 
do 
> > not
> > > > test them now I will simply remove the driver before 8.0 ships.  I no
> > > 
> > > Mea culpa, too. As you sent your patches, I thought someone else will do 
the 
> > > tests surely ... :-(.
> > > 
> > > > longer have any hardware such that I can test this directly, so I am
> > > > depending on folks to test things I have asked for and report back.  I
> > > > believe the last thing I asked for was for someone to do this when 
they 
> > lpt
> > > > was hung:
> > > >
> > > > Ok, can you run kgdb against your running kernel (Just run 'kgdb' 
without
> > > > any arguments) and do the following:
> > > >
> > > > (kgdb) p *(struct ppb_data *)ppbus_devclass->devices[0]->softc
> > > >
> > > > Assuming the ppb_owner is not 0, can you then do this:
> > > >
> > > > (kgdb) p *(device_t)((struct ppb_data
> > > > *)ppbus_devclass->devices[0]->softc)->ppb_owner
> > > 
> > > This is the output (unfortunately ppb_owner IS 0):
> > > 
> > > (kgdb) p *(struct ppb_data *)ppbus_devclass->devices[0]->softc
> > > $1 = {class_id = 10, state = 1, error = 0, mode = 0, ppb_owner = 0x0,
> > >   ppc_lock = 0xc56bfe7c, ppc_irq_res = 0xc573d5c0}
> > 
> > And this is while lpd or the like is hung trying to write to /dev/lpt0?
> > 
> Hello all!
> 
> Ok, here we go. 1st, the system:
> ~> uname -a
> FreeBSD wep4035 8.0-CURRENT FreeBSD 8.0-CURRENT #0: Sat Feb  7 20:25:10 CET 
2009     root_at_wep4035:/usr/obj/usr/src/sys/NOUSB  amd64
> 
> Parallel port (from dmesg):
> ppc0: <Parallel port> port 0x378-0x37f,0x778-0x77f irq 7 drq 3 on acpi0
> ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode
> ppc0: FIFO with 16/16/9 bytes threshold
> ppc0: [ITHREAD]
> ppbus0: <Parallel port bus> on ppc0
> ppbus0: IEEE1284 device found /NIBBLE/ECP
> ppbus0: Probing for PnP devices:
> ppbus0: <HEWLETT-PACKARD OFFICEJET R60> PRINTER MLC,PCL,PML,SCL
> plip0: <PLIP network interface> on ppbus0
> plip0: [ITHREAD]
> lpt0: <Printer> on ppbus0
> lpt0: [ITHREAD]
> lpt0: Interrupt-driven port
> ppi0: <Parallel I/O> on ppbus0
> 
> I have simplified things and do not run lpd. The command is:
> 'ktrace -id cat monitor_info > /dev/lpt0'
> (I think it should work?)
> kdump -E > ktrace.dump does not show anything interesting:
> [snip]
>   1564 cat      0.001120 CALL  open(0x7fffffffee1c,O_RDONLY,<unused>0x6d)
>   1564 cat      0.001127 NAMI  "monitor_info"
>   1564 cat      0.001143 RET   open 3
>   1564 cat      0.001149 CALL  fstat(0x1,0x7fffffffeac0)
>   1564 cat      0.001155 STRU  struct stat {dev=83951360, ino=53, 
mode=crw-rw---
> - , nlink=1, uid=0, gid=0, rdev=53, atime=1234294743.332164000, 
stime=1234294743
> .332164000, ctime=1234294974, birthtime=-1, size=0, blksize=4096, blocks=0, 
flag
> s=0x0 }
>   1564 cat      0.001160 RET   fstat 0
>   1564 cat      0.001180 CALL  
__sysctl(0x7fffffffea20,0x2,0x80085eeb8,0x7ffffff
> fea18,0,0)
>   1564 cat      0.001187 RET   __sysctl 0
>   1564 cat      0.001191 CALL  
__sysctl(0x7fffffffea60,0x2,0x7fffffffea7c,0x7fff
> ffffea70,0,0)
>   1564 cat      0.001198 RET   __sysctl 0
>   1564 cat      0.001203 CALL  
__sysctl(0x7fffffffea60,0x2,0x7fffffffea7c,0x7fffffffea70,0,0)
>   1564 cat      0.001208 RET   __sysctl 0
>   1564 cat      0.001230 CALL  
__sysctl(0x7fffffffe5f0,0x2,0x8008509e8,0x7fffffffe5e8,0,0)
>   1564 cat      0.001236 RET   __sysctl 0
>   1564 cat      0.001242 CALL  readlink(0x800722639,0x7fffffffe610,0x400)
>   1564 cat      0.001248 NAMI  "/etc/malloc.conf"
>   1564 cat      0.001264 RET   readlink -1 errno 2 No such file or directory
>   1564 cat      0.001270 CALL  issetugid
>   1564 cat      0.001275 RET   issetugid 0
>   1564 cat      0.001296 CALL  break(0x600000)
>   1564 cat      0.001302 RET   break 0
>   1564 cat      0.001317 CALL  
__sysctl(0x7fffffffe850,0x2,0x7fffffffe86c,0x7fffffffe860,0,0)
>   1564 cat      0.001324 RET   __sysctl 0
>   1564 cat      0.001329 CALL  mmap(0,0x100000,PROT_READ|
PROT_WRITE,MAP_PRIVATE|MAP_ANON,0xffffffff,0)
>   1564 cat      0.001335 RET   mmap 8790016/0x800862000
>   1564 cat      0.001340 CALL  mmap(0x800962000,0x9e000,PROT_READ|
PROT_WRITE,MAP_PRIVATE|MAP_ANON,0xffffffff,0)
>   1564 cat      0.001346 RET   mmap 9838592/0x800962000
>   1564 cat      0.001351 CALL  munmap(0x800862000,0x9e000)
>   1564 cat      0.001359 RET   munmap 0
>   1564 cat      0.001378 CALL  read(0x3,0x800902000,0x1000)
>   1564 cat      0.006845 GIO   fd 3 read 4096 bytes
>        "(II) VESA(0): VESA VBE DDC supported
>         (II) VESA(0): VESA VBE DDC Level 2
>         (II) VESA(0): VESA VBE DDC transfer in appr. 1 sec.
>         (==) VESA(0): Write-combining range (0x0,0x1000) was already clear
>         (==) VESA(0): Write-combining range (0x0,0x1000) was already clear
> [snip]
>         1 604 625 +hsync +vsync (46.9 kHz)
>         (II) VESA(0): Modeline "800x600"x0.0   50.00  800 856 976 1040  600 
63\
>         7 643 666 +hsync +vsync (48.1 kHz)
>         (II) VESA(0): Modeline "1280x1024"x60.0  108.88  1280 1360 1496 1712  
\
>         1024 1025 1028 1060 -hsync +vsync (63.6 kHz)
>         (II) VESA(0): Modeline "1680x1050"x60.0  147.14  16"
>   1564 cat      0.006879 RET   read 4096/0x1000
>   1564 cat      0.006888 CALL  write(0x1,0x800902000,0x1000)
>   1564 cat      114.695563 RET   write RESTART
>   1564 cat      114.695637 PSIG  SIGINT SIG_DFL
> 
> After 114 seconds I have hit Ctrl-C.
> 
> And this is from kgdb:
> (kgdb) p *(struct ppb_data *)ppbus_devclass->devices[0]->softc
> $1 = {class_id = 0, state = 1, error = 0, mode = 0,
>   ppb_owner = 0xffffff0004668700, ppc_lock = 0xffffff0004668eb8,
>   ppc_irq_res = 0xffffff0004677900}
> (kgdb) p *(device_t)((struct 
ppb_data*)ppbus_devclass->devices[0]->softc)->ppb
> _owner
> $2 = {ops = 0xffffff0001520000, link = {tqe_next = 0xffffff0004668500,
>     tqe_prev = 0xffffff0004668908}, devlink = {tqe_next = 
0xffffff0004668500,
>     tqe_prev = 0xffffff0004668918}, parent = 0xffffff0004669000, children = 
{
>     tqh_first = 0x0, tqh_last = 0xffffff0004668730},
>   driver = 0xffffffff806961c0, devclass = 0xffffff00014f4900, unit = 0,
>   nameunit = 0xffffff0004666940 "lpt0", desc = 0xffffffff804fc110 "Printer",
>   busy = 0, state = DS_ATTACHED, devflags = 0, flags = 7, order = 0 '\0',
>   pad = 0 '\0', ivars = 0xffffff0004668800, softc = 0xffffff0004668400,
>   sysctl_ctx = {tqh_first = 0xffffff0004674180,
>     tqh_last = 0xffffff0004674288}, sysctl_tree = 0xffffff000467d480}
> (kgdb)
> 
> The driver stays in this state even after exit of 'cat' process
> (I think this was already reported):
> ~> cat monitor_info > /dev/lpt0
> /dev/lpt0: Device busy.

Ok, so the first cat works, the second one gets EBUSY?  Can you see if the 
first 'cat' process is still around?

Hmm, I think I've found it.  Due to a bug, lptclose() wasn't releasing the 
bus.

--- //depot/user/jhb/acpipci/dev/ppbus/lpt.c
+++ /home/jhb/work/p4/acpipci/dev/ppbus/lpt.c
_at__at_ -611,11 +611,8 _at__at_
 	int err;
 
 	ppb_lock(ppbus);
-	if (sc->sc_flags & LP_BYPASS) {
-		sc->sc_state = 0;
-		ppb_unlock(ppbus);
+	if (sc->sc_flags & LP_BYPASS)
 		goto end_close;
-	}
 
 	if ((err = lpt_request_ppbus(lptdev, PPB_WAIT|PPB_INTR)) != 0) {
 		ppb_unlock(ppbus);
_at__at_ -635,16 +632,16 _at__at_
 	sc->sc_state &= ~OPEN;
 	callout_stop(&sc->sc_timer);
 	ppb_wctr(ppbus, LPC_NINIT);
-	sc->sc_state = 0;
-	sc->sc_xfercnt = 0;
 
 	/*
 	 * unregistration of interrupt forced by release
 	 */
 	lpt_release_ppbus(lptdev);
-	ppb_unlock(ppbus);
 
 end_close:
+	sc->sc_state = 0;
+	sc->sc_xfercnt = 0;
+	ppb_unlock(ppbus);
 	lprintf(("closed.\n"));
 	return(0);
 }

-- 
John Baldwin
Received on Tue Feb 10 2009 - 20:13:16 UTC

This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:39:42 UTC