Hello all! I'm unsuccessfully struggling w/ DMA support for my Dell D810's DVD drive (`hdparm -d 1 /dev/hdc` fails, and I get poor performances when reading/writing, it even slows down the reactivity of the system). I'm running out of ideas and even of hope, since none of my attempts to get DMA were successful, and reading/writing CD/DVD w/ such prehistoric perfs :-). I tried to customize/rebuild a 2.6.12-1.1381_FC3 kernel to get the following lines in include/linux/libata.h: #define ATA_ENABLE_ATAPI #define ATA_ENABLE_PATA then tried hdc=ide-scsi or hdc=scsi as boot params, loading ide-scsi module thru /etc/rc.local, but nothing works. According to the variety of tests I did, I get or not /dev/hdc, /dev/scd0 or /dev/sr0 (if I add the device node manually), w/ various hdparm reports (read-ahead info present or not) but hdparm always fails to set DMA: /dev/(hdc|sr0|scd0): setting using_dma to 1 (on) HDIO_SET_DMA failed: Invalid argument FYI, w/ default boot params of FC3 kernel, I get: /dev/sda <- the hdd /dev/hdc <- the CD/DVD drive (CD recorder) If I use hdc=ide-scsi, /var/log/messages tells me: kernel: sr0: scsi3-mmc drive: 8x/24x writer cd/rw xa/form2 cdda tray but I'm not that confident that ide-scsi should be used since /var/log/messages tells me: ide-scsi is deprecated for cd burning! Use ide-cd and give dev=/dev/hdX as device Any hint would be welcome, I'm definitely lost now! :-) Can't FC3 kernels (even if modified) enable DMA for such DVD drives? Should I use a vanilla kernel? How to use ide-cd? Is there life on Mars, and hope for me? BTW: noticed that `modprobe -r ide-scsi` simply crashes the kernel, huhu. References: http://cri.ch/linux/docs/sk0010.html http://www.lazy8.nu/delld180/DebianLinuxOnDellLattitude810laptop.html http://casa.colorado.edu/~ajsh/alienware/index.html#DVD http://tkrat.org/d810/ http://fedora.redhat.com/docs/release-notes/fc3/x86/ Regards, -- wwp
