我的电脑是双硬盘，双光驱
hda,hdb是硬盘
hdc,hdd是光驱
现在的主要问题是hdd的那个刻录光驱没法开dma模式
代码： 全选
$ dmesg | grep DMA
[ 0.000000] DMA 0 -> 4096
[ 0.000000] DMA zone: 32 pages used for memmap
[ 0.000000] DMA zone: 0 pages reserved
[ 0.000000] DMA zone: 4064 pages, LIFO batch:0
[ 11.356000] NFORCE-MCP51: 0000:00:0d.0 (rev a1) UDMA133 controller
[ 11.356000] ide0: BM-DMA at 0xf400-0xf407, BIOS settings: hda:DMA, hdb:DMA
[ 11.356000] ide1: BM-DMA at 0xf408-0xf40f, BIOS settings: hdc:DMA, hdd:DMA
[ 13.768000] hdc: ATAPI 40X DVD-ROM drive, 256kB Cache, UDMA(33)
[ 13.768000] hdd: ATAPI 40X DVD-ROM DVD-R-RAM CD-R/RW drive, 2000kB Cache, UDMA(66)
[ 13.808000] hda: 488397168 sectors (250059 MB) w/8192KiB Cache, CHS=30401/255/63, UDMA(100)
[ 13.852000] ata1: SATA max UDMA/133 cmd 0x000109f0 ctl 0x00010bf2 bmdma 0x0001e000 irq 18
[ 13.852000] ata2: SATA max UDMA/133 cmd 0x00010970 ctl 0x00010b72 bmdma 0x0001e008 irq 18
[ 13.924000] hdb: 156301488 sectors (80026 MB) w/2048KiB Cache, CHS=65535/16/63, UDMA(100)
[ 22.504000] parport0: PC-style at 0x378 (0x778), irq 7, dma 3 [PCSPP,TRISTATE,COMPAT,ECP,DMA]
请问怎么可以令我的光驱正常地用dma啊