Version:           0.12.15 (using KDE KDE 3.5.2)
Installed from:    Debian testing/unstable Packages
OS:                Linux

This problem was reported on the Debian bug tracker (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=305551) by Bertrand Maillard <bmaildb@free.fr>:

I tried to burn CD or DVD with GnomeBaker, I tried to burn in command 
line with cdrecord and growisofs, everything is OK.
But as soon as K3b is used, all scsi / usb devices stop working.

Attached devices:
Host: scsi1 Channel: 00 Id: 00 Lun: 00
  Vendor: VBTM     Model: Store 'n' Go     Rev: 1.04
  Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 03 Lun: 00
  Vendor: PLEXTOR  Model: CD-R   PX-W4012S Rev: 1.06
  Type:   CD-ROM                           ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 04 Lun: 00
  Vendor: PLEXTOR  Model: CD-ROM PX-40TS   Rev: 1.05
  Type:   CD-ROM                           ANSI SCSI revision: 02
Host: scsi3 Channel: 00 Id: 00 Lun: 00
  Vendor: HL-DT-ST Model: DVDRAM GSA-4160B Rev: A300
  Type:   CD-ROM                           ANSI SCSI revision: 02

Scsi0 is currently provided by Adaptec 2940UW.
Scsi1 and scsi3 are usb bus.

When trying to access to usb dvd, Syslog gives this:

Jun  6 13:37:24 etch kernel: usb 4-6: USB disconnect, address 3
Jun  6 13:37:24 etch kernel:  2:0:0:0: scsi: Device offlined - not ready 
after error recovery
Jun  6 13:37:24 etch kernel:  2:0:0:0: SCSI error: return code = 0x10000
Jun  6 13:37:24 etch kernel:  2:0:0:0: rejecting I/O to dead device

And all the "usb / scsi" ring is down.
Moreover, the "pure" scsi Plextor CD burner (connected on Adaptec 
2940UW) is only seen as a simple player and trying to access to a disc 
inserted in Plextor 4012 freezes all the KDE

Syslog is quite big :

Jun  6 14:19:03 etch kernel: (scsi0:A:3:0): No or incomplete CDB sent to 
device.
Jun  6 14:19:03 etch kernel: scsi0: Issued Channel A Bus Reset. 1 SCBs 
aborted
Jun  6 14:19:03 etch kernel:  target0:0:3: FAST-20 SCSI 20.0 MB/s ST (50 
ns, offset 15)
Jun  6 14:19:03 etch kernel: (scsi0:A:3:0): No or incomplete CDB sent to 
device.
Jun  6 14:19:03 etch kernel: (scsi0:A:3:0): Protocol violation in 
Message-in phase.  Attempting to abort.
Jun  6 14:20:03 etch kernel: sr 0:0:4:0: Attempting to queue an ABORT 
message
Jun  6 14:20:03 etch kernel: CDB: 0x0 0x0 0x0 0x0 0x0 0x0
Jun  6 14:20:03 etch kernel: scsi0: At time of recovery, card was not 
paused
Jun  6 14:20:03 etch kernel: >>>>>>>>>>>>>>>>>> Dump Card State Begins 
<<<<<<<<<<<<<<<<<
Jun  6 14:20:03 etch kernel: scsi0: Dumping Card State in Message-in 
phase, at SEQADDR 0x170
Jun  6 14:20:03 etch kernel: Card was paused
Jun  6 14:20:03 etch kernel: ACCUM = 0x0, SINDEX = 0x21, DINDEX = 0x65, 
ARG_2 = 0x0
Jun  6 14:20:03 etch kernel: HCNT = 0x0 SCBPTR = 0x0
Jun  6 14:20:03 etch kernel: SCSISIGI[0x14]:(BSYI|ATNI) ERROR[0x0] 
SCSIBUSL[0xf]
Jun  6 14:20:03 etch kernel: LASTPHASE[0xe0]:(MSGI|IOI|CDI) 
SCSISEQ[0x12]:(ENAUTOATNP|ENRSELI)
Jun  6 14:20:03 etch kernel: SBLKCTL[0x2]:(SELWIDE) SCSIRATE[0xf]:
(SXFR_ULTRA2)
Jun  6 14:20:03 etch kernel: SEQCTL[0x10]:(FASTMODE) SEQ_FLAGS[0x40]:
(NO_CDB_SENT)
Jun  6 14:20:03 etch kernel: SSTAT0[0x0] SSTAT1[0x2]:(PHASECHG) SSTAT2
[0xe]:(CRCREQERR|CRCENDERR|CRCVALERR)
Jun  6 14:20:03 etch kernel: SSTAT3[0x0] SIMODE0[0x0] SIMODE1[0xac]:
(ENSCSIPERR|ENBUSFREE|ENSCSIRST|ENSELTIMO)
Jun  6 14:20:03 etch kernel: SXFRCTL0[0xa8]:(SPIOEN|FAST20|DFON) 
DFCNTRL[0x4]:(DIRECTION)
Jun  6 14:20:03 etch kernel: DFSTATUS[0x6d]:(FIFOEMP|DFTHRESH|HDONE|
FIFOQWDEMP|DFCACHETH)
Jun  6 14:20:03 etch kernel: STACK: 0x37 0x61 0x0 0x19a
Jun  6 14:20:03 etch kernel: SCB count = 4
Jun  6 14:20:03 etch kernel: Kernel NEXTQSCB = 3
Jun  6 14:20:03 etch kernel: Card NEXTQSCB = 2
Jun  6 14:20:03 etch kernel: QINFIFO entries: 2
Jun  6 14:20:03 etch kernel: Waiting Queue entries:
Jun  6 14:20:03 etch kernel: Disconnected Queue entries:
Jun  6 14:20:03 etch kernel: QOUTFIFO entries:
Jun  6 14:20:03 etch kernel: Sequencer Free SCB List: 1 2 3 4 5 6 7 8 9 
10 11 12 13 14 15
Jun  6 14:20:03 etch kernel: Sequencer SCB Info:
Jun  6 14:20:03 etch kernel:   0 SCB_CONTROL[0xc8]:(ULTRAENB|DISCENB|
TARGET_SCB) SCB_SCSIID[0x37]
Jun  6 14:20:03 etch kernel: SCB_LUN[0x0] SCB_TAG[0x1]
Jun  6 14:20:03 etch kernel:   1 SCB_CONTROL[0xc8]:(ULTRAENB|DISCENB|
TARGET_SCB) SCB_SCSIID[0x47]
Jun  6 14:20:03 etch kernel: SCB_LUN[0x0] SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:   2 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:   3 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:   4 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:   5 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:   6 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:   7 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:   8 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:   9 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:  10 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:  11 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:  12 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:  13 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:  14 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel:  15 SCB_CONTROL[0x0] SCB_SCSIID[0xff]:
(TWIN_CHNLB|OID|TWIN_TID)
Jun  6 14:20:03 etch kernel: SCB_LUN[0xff]:(SCB_XFERLEN_ODD|LID) 
SCB_TAG[0xff]
Jun  6 14:20:03 etch kernel: Pending list:
Jun  6 14:20:03 etch kernel:   2 SCB_CONTROL[0x50]:(MK_MESSAGE|DISCENB) 
SCB_SCSIID[0x47]
Jun  6 14:20:03 etch kernel: SCB_LUN[0x0]
Jun  6 14:20:03 etch kernel:   1 SCB_CONTROL[0x48]:(ULTRAENB|DISCENB) 
SCB_SCSIID[0x37]
Jun  6 14:20:03 etch kernel: SCB_LUN[0x0]
Jun  6 14:20:03 etch kernel: Kernel Free SCB list: 0
Jun  6 14:20:03 etch kernel: Untagged Q(3): 1
Jun  6 14:20:03 etch kernel: Untagged Q(4): 2
Jun  6 14:20:03 etch kernel:
Jun  6 14:20:03 etch kernel: <<<<<<<<<<<<<<<<< Dump Card State Ends 
>>>>>>>>>>>>>>>>>>
Jun  6 14:20:03 etch kernel: scsi0:0:4:0: Cmd aborted from QINFIFO
Jun  6 14:20:03 etch kernel: aic7xxx_abort returns 0x2002


You're welcome if someone needs more informations.

Bertrand