Enabling DMA

paragkalra · 03-28-2008, 08:47 PM

Hello Folks,

I have HP 7400 DX Tower. I have installed two Operating Systems on it:
1.] SLES 10 SP1
2.] RHEL 5.1

SLES has recognized the hard-disk as /dev/sda where as RHEL has recognized it as /dev/hda which means that RHEL has not enabled the DMA. How can I enable DMA? Also copying chunk of data on RHEL is taking years where as in SLES it is getting copied like a charm. Please help.

slackhack · 03-28-2008, 09:08 PM

hdparm -d1 /dev/hda would be the most basic command. but there are other options depending on your disk. hdparm -i /dev/hda will give you info on the disk, and then hdparm -h will list the options you can use (or man hdparm for more detail).

Bruce Hill · 03-28-2008, 11:02 PM

It sounds like SLES has found a S-ATA drive, and RHEL thinks it's P-ATA

knappster · 03-29-2008, 06:52 PM

Both posts above are correct as far as I'm aware. Do you have more than 1 hard drive? Perhaps SLES is installed on a SATA hard drive and RHEL is installed on a PATA hard drive?

SDA and HDA are not referring to DMA enabled, just the types of drives used.

Be sure that the parallel drive has an 80-pin IDE cable, because DMA won't work with a 40-pin IDE cable.

osor · 03-29-2008, 08:46 PM

Quote:

Originally Posted by Bruce Hill

It sounds like SLES has found a S-ATA drive, and RHEL thinks it's P-ATA

Not necessarily. On newer kernels (using libata) all SATA and PATA drives all show up as sd?. It has nothing to do with DMA (which as mentioned before can be checked for PATA drives with hdparm).

konsolebox · 03-29-2008, 09:51 PM

can we have the output of

Code:

dmesg | grep -e '^hda' -e '^sd'

Bruce Hill · 03-29-2008, 11:53 PM

Quote:

Originally Posted by osor

Not necessarily. On newer kernels (using libata) all SATA and PATA drives all show up as sd?. It has nothing to do with DMA (which as mentioned before can be checked for PATA drives with hdparm).

Which distro compiles a kernel with no P-ATA support?

I dare say none, since the majority of hard disks and ROM drives are still ATA (now called P-ATA).

osor · 03-30-2008, 12:36 PM

Quote:

Originally Posted by Bruce Hill

Which distro compiles a kernel with no P-ATA support?

I never said no PATA support. I said PATA support through libata. In this case your PATA drive will still be there (and still be PATA), but it will show up as a block device labeled /dev/sda or similar (instead of the older /dev/hda).

Bruce Hill · 03-30-2008, 08:57 PM

Okay, I didn't word it correct, so you can split hairs.

What I should have said is "Which distro compiles a kernel with no IDE support?" I am referring to kernel support for IDE hard drives and ATAPI CD-ROM drives. Does that make it clear enough?

There are Serial ATA drives (SATA) and Parallel ATA drives (PATA). However, the term PATA is being used in place of IDE a lot now. That's what I erroneously thought you were doing. Sorry.

I happen to have a custom 2.6.24.4 kernel for testing with

Code:

CONFIG_SATA_VIA=y
CONFIG_PATA_VIA=y

and no IDE modules, so I'm not ignorant to the fact that they don't show up as hd*. These are my four ATA drives:

Code:

mingdao@silas:~$ dmesg | grep -i -e '^ata' -e '^scsi'
SCSI subsystem initialized
scsi0 : sata_via
scsi1 : sata_via
ata1: SATA max UDMA/133 cmd 0xe400 ctl 0xe000 bmdma 0xd000 irq 17
ata2: SATA max UDMA/133 cmd 0xd800 ctl 0xd400 bmdma 0xd008 irq 17
ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata1.00: ATA-6: WDC WD740GD-00FLC0, 33.08F33, max UDMA/133
ata1.00: 145226112 sectors, multi 16: LBA48
ata1.00: configured for UDMA/133
ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata2.00: ATAPI: ASUS    DRW-2014L1T, 1.00, max UDMA/66
ata2.00: configured for UDMA/66
scsi 0:0:0:0: Direct-Access     ATA      WDC WD740GD-00FL 33.0 PQ: 0 ANSI: 5
scsi 1:0:0:0: CD-ROM            ASUS     DRW-2014L1T      1.00 PQ: 0 ANSI: 5
scsi2 : pata_via
scsi3 : pata_via
ata3: PATA max UDMA/133 cmd 0x1f0 ctl 0x3f6 bmdma 0xfc00 irq 14
ata4: PATA max UDMA/133 cmd 0x170 ctl 0x376 bmdma 0xfc08 irq 15
ata3.00: ATAPI: TSSTcorpCD/DVDW TS-H552U, US06, max UDMA/33
ata3.00: configured for UDMA/33
ata4.00: ATA-7: ST3802110A, 3.AAE, max UDMA/100
ata4.00: 156301488 sectors, multi 16: LBA48
ata4.00: configured for UDMA/100
scsi 2:0:0:0: CD-ROM            TSSTcorp CD/DVDW TS-H552U US06 PQ: 0 ANSI: 5
scsi 3:0:0:0: Direct-Access     ATA      ST3802110A       3.AA PQ: 0 ANSI: 5
scsi 1:0:0:0: Attached scsi generic sg1 type 5
scsi 2:0:0:0: Attached scsi generic sg2 type 5

However, the point you missed, that I was trying to make, is that hopefully there are no distros shipping a kernel without IDE support. If so, then the IDE drive will be detected as /dev/sd* as you mentioned, but the kernel will not be able to change PIO, DMA and UDMA speeds and to configure the chip to optimum performance.

osor · 03-31-2008, 03:37 PM

Quote:

Originally Posted by Bruce Hill

If so, then the IDE drive will be detected as /dev/sd* as you mentioned, but the kernel will not be able to change PIO, DMA and UDMA speeds and to configure the chip to optimum performance.

I was unaware that this was even possible. I thought that either is detected in full or not at all. Thank you for that information.

Bruce Hill · 03-31-2008, 09:52 PM

Another thing I found using libata only, is my DVD drives show up as /dev/sr*.
At the present time I don't know how much of that is strictly coming from libata,
and how much is due to Udev/HAL/D-Bus as configured in Slackware.

I have problems with my new ASUS DRW-2014L1T (SATA DVD+/-RW) drive. It will read
media, but will not burn with cdrecord, cdrdao, growisofs ... neither from CLI or
using K3B. And furthermore, atm I can't determine where the bug is located.