Re: IDE CDROM - No DMA

[Parag Warudkar <kernel-stuff@comcast.net>]

On Friday 10 March 2006 18:42, Parag Warudkar wrote:
> I have a "TSSTCorp"  CD-RW/DVD Drive in my laptop
> which is IDE1.  DMA is not enabled on this drive. (Copying from CDROM
> stalls the machine - conforming that DMA is not really in use.)
>
Hmm.. Interestingly this seems to be a IDE layer problem not specific to the 
drive in question. No matter what CD / DVD drive I put into my lapatop DMA is 
not enabled. (I tried replacing this TSSTCorp drive with a  Pioneer drive 
which was doing DMA fine with Linux on another machine, but with this laptop, 
I can't set DMA on it.)

Any clues, workarounds, hint of a place to start debugging this?
Some relevant snippets from dmesg -
------------------------------------------------------------------------
PCI: Ignoring BAR0-3 of IDE controller 0000:00:1f.2
Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
ide0: I/O resource 0x1F0-0x1F7 not free.
ide0: ports already in use, skipping probe
Probing IDE interface ide1...
ide1 at 0x170-0x177,0x376 on irq 15
ata: 0x170 IDE port busy
hdc: PIONEER DVD-RW DVR-K05, ATAPI CD/DVD-ROM drive
ide1 at 0x170-0x177,0x376 on irq 15
hdc: ATAPI 24X DVD-ROM DVD-R CD-R/RW drive, 2000kB Cache
Uniform CD-ROM driver Revision: 3.20
libata version 1.20 loaded.
ata_piix 0000:00:1f.2: version 1.05
ACPI: PCI Interrupt 0000:00:1f.2[B] -> GSI 17 (level, low) -> IRQ 177
ata: 0x170 IDE port busy
PCI: Setting latency timer of device 0000:00:1f.2 to 64
ata1: SATA max UDMA/133 cmd 0x1F0 ctl 0x3F6 bmdma 0xBFA0 irq 14
ata1: dev 0 cfg 49:2f00 82:746b 83:7f09 84:6023 85:7469 86:3e09 87:6023 
88:203f
ata1: dev 0 ATA-6, max UDMA/100, 153356490 sectors: LBA48
ata1: dev 0 configured for UDMA/100
scsi0 : ata_piix
  Vendor: ATA       Model: TOSHIBA MK8032GS  Rev: AS11
  Type:   Direct-Access                      ANSI SCSI revision: 05
SCSI device sda: 153356490 512-byte hdwr sectors (78519 MB)
SCSI device sda: drive cache: write back
SCSI device sda: 153356490 512-byte hdwr sectors (78519 MB)
SCSI device sda: drive cache: write back
 sda: sda1 sda2 sda3 sda4
sd 0:0:0:0: Attached scsi disk sda
sd 0:0:0:0: Attached scsi generic sg0 type 0
ieee1394: Initialized config rom entry `ip1394'

Thanks
Parag