Re: SOLVED: Problems with cdparanoia

Here is the setup I always use which works well...

(1) At compile time-
	(a) ide atapi cdrom _off_
	(b) scsi cdrom support _on_
	(c) scsi generic support _on_

(2) So we can read the cdrom with the expected device	
	ln -s /dev/sr0 /dev/cdrom

(3) For writing to the cdrom, use device /dev/sg0  (or, on some systems, /dev/scd0)

If set up this way, it is not necessary to pass 'hdx=ide-scsi' to the kernel at boot. The messages at boot will include something like this:

 hdc: LITE-ON LTR-12101B, ATAPI CD/DVD-ROM drive
  <snip>
 SCSI subsystem driver Revision: 1.00
 scsi0 : SCSI host adapter emulation for IDE ATAPI devices
    Vendor: LITE-ON   Model: LTR-12101B        Rev: LS3B
    Type:   CD-ROM                             ANSI SCSI revision: 02
 Attached scsi CD-ROM sr0 at scsi0, channel 0, id 0, lun 0
 Uniform CD-ROM driver Revision: 3.12
 sr0: scsi3-mmc drive: 32x/32x writer cd/rw xa/f

indicating that scsi driver "got it". You won't be able to use (or need) the /dev/hdc device.

-Ted




On 02 Dec 2002 01:43:29 -0700
Kim Lux <[email protected]> wrote:

> Hi people
> 
> Disclaimer: I'm a linux newbie.  Some of this may be incorrect. 
> 
> I spent a good day troubleshooting cdparanoia crashing my RH8 linux
> install.  I traced the problem to a conflict between two kernel options
> involving SCSI operation of an IDE/ATAPI CDROM drive. 
> 
> Related posts: "What is the difference between /dev/sg0, /dev/scd0..."
> and
> "cdparanoia crashes linx, hdd loses interrupt, can't kill process" 
> These
> posts were made to linux.redhat, etc. over the weekend. 
> 
> Background Info
> 
> Frequently, certain CDROM applications ie cdparanoia and cd burning
> require
> SCSI access to an IDE/ATAPI CDROM device because it offers a richer set
> of features
> to control it.
> 
> The default manner of CDROM control in a stock Linux kernel is via the
> ATAPI interface.  In fact, it appears to me that unless the ATAPI
> interface is turned off as a kernel option, the CDROM drive will be
> accessed
> this way no matter what options might be selected elsewhere. (Ie: grub
> and
> lilo)
> 
> Symptoms Of a IDE/ATAPI SCSI CDROM Problem
> 
> - linux crashes or becomes unresponsive when accessing the CDROM
> - the message "hdx lost interrupt" appears (x = CDROM drive)
> - CDROM applications hang
> - improper operation of the CDROM in general
> - your operation require SCSI CDROM access
> - a dirty dmesg printout after CDROM operation
> - the process using the CDROM won't kill after crashing
> 
> Root Problem
> 
> IDE-ATAPI CDROM operation becomes unstable under SCSI emulation if both
> of the following options are
> selected:
> 
> a) SCSI CDROM Support
> b) IDE-SCSI Emulation
> 
> SCSI CDROM support is enabled to allow the use of a true SCSI CDROM
> IDE-SCSI Emulation is enabled to allow Linux to emulate a SCSI CDROM
> when
> accessing an IDE CDROM.
> 
> WARNING: There may be more to this issue than resolving these two
> options.
> My CDROM works OK with these two options resolved.  Others are saying
> that
> they need to disable all the low level SCSI drivers in the kernel.    
> 
> 
> So... to set a CDROM up for SCSI access, one should perform the
> following:
> 
> a) check that the line hdx=ide-scsi appears in your boot loader (ie lilo
> or
> grup.) x = the position of the cdrom drive ie hda for primary master,
> hdb
> for primary slave, hdc for secondary master, etc.  This line will
> request
> that linux operate the CDROM in SCSI emulation mode 
> 
> b) in the kernel options, the ATAPI CDROM support MUST be turned OFF. 
> This option is selected under ATA/IDE/MFM/RLL Support-> ATA/IDE.. Block
> Devices-> Include IDE/ATAPI CDROM Support.  Turning this option off will
> force Linux to access the CDROM by another method. 
> 
> c) in the kernel options, in the same area, SCSI Emulation Support must
> be
> turned ON.  This allows Linux to access the EDI/ATAPI CDROM via the SCSI
> emulation interface.  
> 
> d) in the kernel options, Under SCSI Support, turn off SCSI CDROM
> Support.
>  SCSI CDROM Support is used to access a real SCSI CDROM.       
> 
> e) in /dev/, set the /cdrom link to point to /hdd.  Actually I am not
> sure
> about this.
> 
> f) It might or might not help to disable autorun or at least disable the
> CDROM player application from attempting to control the CDROM device. 
> 
> I hope this helps someone. 
> 
> Nobody
> 
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