Re: writable mmc profiles actually are writable

Pat LaVarre
2003-10-10T23:16:37Z

I have a new guess of precisely when we want cdrom to probe for
capabilities beyond those discovered by ide-cd and sr.

I'm now guessing we want to author additional cdb's at the end of
register_cdrom, just after such optional messages as 'cdrom: drive
"/dev/sr0" registered'.

To leap to that conclusion, I reasoned as follows. Somebody tell me how
wrong I am?

Pat LaVarre

1)

I found cdrom.c ERRLOGMASK. I see our default is to pass thru just the
CD_WARNING cdrom: messages. I see the last commented-out #define means
pass thru all the defined types of cdrom: messages.

2)

I see with usb cdb's unmasked, hot plug spews the dmesg:

Initializing USB Mass Storage driver...
scsi0 : SCSI emulation for USB Mass Storage devices
x 12 00 00 00 24 00
x 12 00 00 00 C0 00
Vendor: Iomega Model: RRD Rev: 36.D
Type: CD-ROM ANSI SCSI revision: 02
WARNING: USB Mass Storage data integrity not assured
USB Mass Storage device found at 2
drivers/usb/core/usb.c: registered new driver usb-storage
USB Mass Storage support registered.
updfstab: numerical sysctl 1 23 is obsolete.

3)

I see with cdrom messages also unmasked, the one block write `sudo dd
of=/dev/scd0 bs=2K count=1 if=/dev/zero` provokes the spew:

x 00 00 00 00 00 00
x 03 00 00 00 12 00
x 00 00 00 00 00 00
x 5A 00 2A 00 00 00 00 00 80 00
sr0: scsi3-mmc drive: 125x/125x caddy
cdrom: entering register_cdrom
Uniform CD-ROM driver Revision: 3.12
cdrom: drive "/dev/sr0" registered
Attached scsi CD-ROM sr0 at scsi0, channel 0, id 0, lun 0
cdrom: entering cdrom_open
cdrom_cdc_mmc_wr
cdrom: entering open_for_data
x 00 00 00 00 00 00
cdrom: drive_status=4
cdrom: entering cdrom_count_tracks
x 43 00 00 00 00 00 00 00 0C 00
x 43 02 00 00 00 00 01 00 0C 00
cdrom: track 1: format=2, ctrl=4
cdrom: disc has 1 tracks: 0=audio 1=data 0=Cd-I 0=XA
cdrom: all seems well, opening the device.
x 25 00 00 00 00 00 00 00 00 00
cdrom: opening the device gave me 0.
x 1E 00 00 00 01 00
cdrom: door locked.
cdrom: device opened successfully.
cdrom: Use count for "/dev/sr0" now 1
x 00 00 00 00 00 00
x 43 00 00 00 00 00 00 00 0C 40
x 43 00 00 00 00 00 00 00 0C 00
x 43 00 00 00 00 00 01 00 0C 00
x 28 00 00 00 00 00 00 00 02 00
x 2A 00 00 00 00 00 00 00 02 00
cdrom: entering cdrom_release
cdrom: Use count for "/dev/sr0" now zero
cdrom: Unlocking door!
x 1E 00 00 00 00 00