Again... DMA speed too slow

["J.A. Magallón" <jamagallon@ono.com>]

Hi all...

I have tried to burn some data from the commandline with wodim (since time
ago I just used beasero...), and I have noticed this (media is CD, not DVD):

Vendor_info    : 'HL-DT-ST'
Identification : 'DVDRAM GSA-H10N '
Revision       : 'JL12'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
Using generic SCSI-3/mmc   CD-R/CD-RW driver (mmc_cdr).
Driver flags   : MMC-3 SWABAUDIO BURNFREE
Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R
Speed set to 8467 KB/s
wodim: DMA speed too slow (OK for 5x). Cannot write at speed 48x.
Starting to write CD/DVD at speed  48.0 in real TAO mode for single session.

I just can burn CDs at 5x ??
But then the program tries to write at 48x.
It the DMA message really true ?

Accodring to wodim -prcap:

  Maximum read  speed: 22161 kB/s (CD 125x, DVD 16x)
  Current read  speed: 22161 kB/s (CD 125x, DVD 16x)
  Maximum write speed: 11080 kB/s (CD  62x, DVD  8x)
  Current write speed: 11080 kB/s (CD  62x, DVD  8x)
  Rotational control selected: CLV/PCAV
  Buffer size in KB: 2048
  Copy management revision supported: 1
  Number of supported write speeds: 3
  Write speed # 0: 11080 kB/s CLV/PCAV (CD  62x, DVD  8x)
  Write speed # 1:  5540 kB/s CLV/PCAV (CD  31x, DVD  4x)
  Write speed # 2:  3324 kB/s CLV/PCAV (CD  18x, DVD  2x)

Why the tests in wodim say that DMA to the drive is slow ?

Kernel is 2.6.24.4.
The drive is controlled by libata+sata_promise:

sata_promise 0000:03:04.0: version 2.11
ACPI: PCI Interrupt 0000:03:04.0[A] -> GSI 23 (level, low) -> IRQ 17
scsi6 : sata_promise
scsi7 : sata_promise
scsi8 : sata_promise
ata5: SATA max UDMA/133 mmio m4096@0xf6029000 port 0xf6029200 irq 17
ata6: SATA max UDMA/133 mmio m4096@0xf6029000 port 0xf6029280 irq 17
ata7: PATA max UDMA/133 mmio m4096@0xf6029000 port 0xf6029300 irq 17
ata5: SATA link down (SStatus 0 SControl 300)
ata6: SATA link down (SStatus 0 SControl 0)
ata7.00: ATA-6: ST3120022A, 3.06, max UDMA/100
ata7.00: 234441648 sectors, multi 0: LBA48
ata7.01: ATAPI: HL-DT-ST DVDRAM GSA-H10N, JL12, max UDMA/33
ata7.00: configured for UDMA/100
ata7.01: configured for UDMA/33
scsi 8:0:0:0: Direct-Access     ATA      ST3120022A       3.06 PQ: 0 ANSI: 5
sd 8:0:0:0: [sdd] 234441648 512-byte hardware sectors (120034 MB)
sd 8:0:0:0: [sdd] Write Protect is off
sd 8:0:0:0: [sdd] Mode Sense: 00 3a 00 00
sd 8:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 8:0:0:0: [sdd] 234441648 512-byte hardware sectors (120034 MB)
sd 8:0:0:0: [sdd] Write Protect is off
sd 8:0:0:0: [sdd] Mode Sense: 00 3a 00 00
sd 8:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
 sdd: sdd1
sd 8:0:0:0: [sdd] Attached SCSI disk
sd 8:0:0:0: Attached scsi generic sg3 type 0
scsi 8:0:1:0: CD-ROM            HL-DT-ST DVDRAM GSA-H10N  JL12 PQ: 0 ANSI: 5
sr0: scsi3-mmc drive: 48x/48x writer dvd-ram cd/rw xa/form2 cdda tray

UDMA/33 on the burner should be ok for 48x (150x48 = 7.2 MB/s) ?
Or just 16x, as I read elsewhere ?

TIA

-- 
J.A. Magallon <jamagallon()ono!com>     \               Software is like sex:
                                         \         It's better when it's free
Mandriva Linux release 2008.1 (Cooker) for i586
Linux 2.6.23-jam05 (gcc 4.2.2 20071128 (4.2.2-2mdv2008.1)) SMP PREEMPT