Dominique Dumont <[EMAIL PROTECTED]> wrote: > scsidev: 'ATAPI:0,0,0' > devname: 'ATAPI' > scsibus: 0 target: 0 lun: 0 > Warning: Using ATA Packet interface. > Warning: The related Linux kernel interface code seems to be > unmaintained. Warning: There is absolutely NO DMA, operations thus > are slow. Using libscg version 'schily-0.8'.
> The part about no DMA is weird since hdparm reports that DMA is > enabled: $ sudo hdparm /dev/hdc > > /dev/hdc: > IO_support = 0 (default 16-bit) > unmaskirq = 1 (on) > using_dma = 1 (on) > keepsettings = 0 (off) > readonly = 0 (off) > readahead = 256 (on) > HDIO_GETGEO failed: Invalid argument > > Could someone tell me what's wrong ? Reading the error/warning output could. I quoted the relevant part above. You're using the unbelievably old, very, very deprecated "ATAPI" device interface. This API does not support DMA at all. The fact that using_dma is on is irrelevant; this API disables DMA no matter what. Solution: Address the drive as "ATA:0,0,0" instead of "ATAPI:0,0,0". Note: Noone can guarantee that DMA will work using ATA:. The Linux kernel drivers seem to be generally crappy in this area. But with this API, there's at least a theoretical chance for DMA. @JÃrg: Is it actually useful to keep this interface around? Any real-world reason to use it? I suggest removing it and aliasing ATAPI: to ATA: in future versions. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
