Administrace komentářů

Takže pan Čihař na to asi kápl.

V tom výpisu totiž stojí, že vaše cdrom pravděpodobně "neumí DMA". Ale umí multiword DMA, nebo ultra dma, takže bych se podíval do man hdparm na parametr -X (velké X).

Akorát mi není jasné, proč to -d1 nezapne nějaké default DMA.

       -X     Set  the IDE transfer mode for newer (E)IDE/ATA drives.  This is
              typically used in combination with -d1 when enabling DMA to/from
              a drive on a supported interface chipset, where -X mdma2 is used
              to select multiword DMA mode2 transfers and -X sdma1 is used  to
              select  simple mode 1 DMA transfers.  With systems which support
              UltraDMA burst timings, -X udma2  is  used  to  select  UltraDMA
              mode2 transfers (you'll need to prepare the chipset for UltraDMA
              beforehand).  Apart from that, use of this flag is seldom neces-
              sary  since  most/all modern IDE drives default to their fastest
              PIO transfer mode at power-on.  Fiddling with this can  be  both
              needless  and risky.  On drives which support alternate transfer
              modes, -X can be used to switch the  mode  of  the  drive  only.
              Prior to changing the transfer mode, the IDE interface should be
              jumpered or programmed (see -p flag) for the new mode setting to
              prevent  loss  and/or corruption of data.  Use this with extreme
              caution!  For the PIO (Programmed Input/Output)  transfer  modes
              used  by Linux, this value is simply the desired PIO mode number
              plus 8.  Thus, a value of 09 sets  PIO  mode1,  10  enables  PIO
              mode2,  and  11  selects  PIO  mode3.   Setting  00 restores the
              drive's "default" PIO mode, and 01 disables IORDY.   For  multi-
              word DMA, the value used is the desired DMA mode number plus 32.
              for UltraDMA, the value is the desired UltraDMA mode number plus
              64.