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Hardware / Úplný zákaz DMA a UDMA

« kdy: 16. 05. 2011, 16:03:45 »

Zdravim vsechny, snazim se uplne zakazat DMA a UDMA na /dev/sda. Bohuzel se mi to uplne nedari, dokazu zakazat UDMA, ale i pres vynuceni libata.nodma=0 hdparm stale reportuje vyuziti DMA. Mam podezreni, ze to vede na potize se stabilitou stroje. Mate nekdo zkusenosti s podobnym chovanim libata? (jadro 2.6.32)

Diky

V.

Kód: [Vybrat]

# dmesg
...
ata1.00: CFA: 1GB CompactFlash Card, CF B61FK, max UDMA/66
ata1.00: 2001888 sectors, multi 0: LBA
ata1.00: limited to UDMA/33 due to 40-wire cable
[b]ata1.00: FORCE: xfer_mask set to pio4
ata1.00: configured for PIO4
ata1.00: FORCE: xfer_mask set to pio4
ata1.00: configured for PIO4[/b]
ata1: EH complete
scsi 0:0:0:0: Direct-Access     ATA      1GB CompactFlash CF B PQ: 0 ANSI: 5
sd 0:0:0:0: [sda] 2001888 512-byte logical blocks: (1.02 GB/977 MiB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 0:0:0:0: Attached scsi generic sg0 type 0
 sda: sda1
sd 0:0:0:0: [sda] Attached SCSI disk
...

# cat /proc/cmdline
root=UUID=fb2d07f0-cd8f-4cba-a042-83275fab9d1d ro debug [b]libata.force=pio4[/b]

# hdparm -I /dev/sda

/dev/sda:

ATA device, with non-removable media
        Model Number:       1GB CompactFlash Card
        Firmware Revision:  CF B61FK
Standards:
        Likely used: 4
Configuration:
        Logical         max     current
        cylinders       1986    1986
        heads           16      16
        sectors/track   63      63
        --
        bytes/track: 0  bytes/sector: 512
        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(cannot be disabled)
        Buffer size: 1.0kB      bytes avail on r/w long: 4
        Standby timer values: spec'd by Vendor
        R/W multiple sector transfer: Max = 1   Current = 0
        Advanced power management level: disabled
        [b]DMA: mdma0 mdma1 *mdma2 udma0 udma1 udma2 udma3 udma4[/b]
             Cycle time: min=120ns recommended=120ns
        PIO: pio0 pio1 pio2 pio3 pio4
             Cycle time: no flow control=120ns  IORDY flow control=120ns