Ultra DMA

[James]

tohle funguje pouze na hda, ktery v pohode nadetekoval bios... udma funguje
bez problemu...
na hdc a hdd udma nastavit nejde... kdyz to nastavim tak se pri prvnim
pristupu na disk se udma vypne...

viz>>
...proste pokud ten disk neni nadetekovany v biosu, tak dma nejak nechodi...
>>>
xxx:~# hdparm -I /dev/hdc

/dev/hdc:

 Model=UQNAUT MIFERABLL PSA040.                , FwRev=1A.Y3100,
SerialNo=980443327552
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
 RawCHS=16383/16/63, TrkSize=32256, SectSize=21298, ECCbytes=4
 BuffType=DualPortCache, BuffSize=1902kB, MaxMultSect=16, MultSect=16
 CurCHS=16383/16/63, CurSects=-66060037, LBA=yes, LBAsects=78177792
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes: pio0 pio1 pio2 pio3 pio4
 DMA modes: mdma0 mdma1 *mdma2 udma0 udma1 udma2 udma3 udma4 udma5
------------------
nastavim treba udma2 >>>
xxx:~# hdparm -c1 -d1 -X66 -m16 /dev/hdc

/dev/hdc:
 setting 32-bit I/O support flag to 1
 setting multcount to 16
 setting using_dma to 1 (on)
 setting xfermode to 66 (UltraDMA mode2)
 multcount    = 16 (on)
 I/O support  =  1 (32-bit)
 using_dma    =  1 (on)
----------------
...ted kdyz si dam hdparm -I tam je hvezdicka u udma2
...kdyz dam hdparm -v tak je dma zapnuty
...pustim test rychlosti (nebo jakykoliv jiny pokus o pristup na ten
disk)>>>
xxx:~# hdparm -tT /dev/hdc

/dev/hdc:
 Timing buffer-cache reads:   128 MB in  1.18 seconds =108.47 MB/sec
 Timing buffered disk reads:  64 MB in 29.08 seconds =  2.20 MB/sec
-----------------
....kouknu znova jak je na tom ten disk
xxx:~# hdparm -v /dev/hdc

/dev/hdc:
 multcount    = 16 (on)
 I/O support  =  1 (32-bit)
 unmaskirq    =  0 (off)
 using_dma    =  0 (off)
 keepsettings =  0 (off)
 nowerr       =  0 (off)
 readonly     =  0 (off)
 readahead    =  8 (on)
 geometry     = 12021/16/63, sectors = 78177792, start = 0