Hi folks, hdparm's got me confused.
I've got an old PC with an ALi Corporation MS4803 (rev 01) IDE controller.
According to the manufacturer, this controller does NOT support DMA,
only PIO 0-4. I'm booting off various Sandisk Compact Flash cards,
which I believe all support both PIO and DMA.
I'm using hdparm 6.1, and I get practically identical results with 2.4.32
and 2.6.15.4.
"hdparm /dev/hda" says:
/dev/hda:
multcount = 0 (off)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 0 (off)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 1986/16/63, sectors = 2001888, start = 0
"hdparm -I /dev/hda" says:
CompactFlash ATA device, with removable media
Model Number: SanDisk SDCFH-1024
Serial Number: 003305F1104P3318
Firmware Revision: HDX 2.18
Standards:
Supported: 10
Likely used: 10
Configuration:
Logical max current
cylinders 1986 1986
heads 16 16
sectors/track 63 63
--
CHS current addressable sectors: 2001888
LBA user addressable sectors: 2001888
device size with M = 1024*1024: 977 MBytes
device size with M = 1000*1000: 1024 MBytes (1 GB)
Capabilities:
LBA, IORDY(may be)(cannot be disabled)
Queue depth: 1
Standby timer values: spec'd by Vendor
R/W multiple sector transfer: Max = 1 Current = 1
DMA: mdma0 mdma1 *mdma2
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=120ns IORDY flow control=120ns
The "hdparm" output shows using_dma is off. That's refering the the
HBA, right?
As I understand the "hdparm -I" output, however, it claims the drive
(not the HBA) is using mdma2. Is that right? How can the drive and
the HBA use different modes?
I thought the HBA and the drive(s) would automatically use the fastest
mode that both devices support, which in this case should be PIO4.
I tried to manually switch the HBA to pio4 with "hdparm -p4 /dev/hda"
but got this error:
/dev/hda:
attempting to set PIO mode to 4
HDIO_SET_PIO_MODE failed: Function not implemented
Manually switching the drive to pio4 with "hdparm -X pio4 /dev/hda"
seems to work:
/dev/hda:
setting xfermode to 12 (PIO flow control mode4)
But even after running this, "hdparm -I /dev/hda" shows it using mdma2
(with the * by it).
BTW, here's the relevant part of dmesg, from 2.4.32:
Uniform Multi-Platform E-IDE driver Revision: 7.00beta4-2.4
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
hda: SanDisk SDCFH-1024, CFA DISK drive
ide2: ports already in use, skipping probe
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
hda: attached ide-disk driver.
hda: 2001888 sectors (1025 MB) w/1KiB Cache, CHS=1986/16/63
Partition check:
hda: hda1 hda2 hda3
Please clue in a poor monkey - what is going on here?
--
Sebastian Kuzminsky
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