On Thu, 2006-05-25 at 09:14 -0300, Marcelo Magno T. Sales wrote: > Hi, > > I have several desktop machines and notebooks which have CDROM / DVDROM > connected to IDE SATA interfaces and they all have DMA disabled. Every time > the CDROM/DVDROM drives are accessed, the computers slow down a lot and > become almost unusable till it's finished. hdparm shows: > [marcelo.sales@sf002698 ~]$ /sbin/hdparm /dev/dvd > > /dev/dvd: > IO_support = 0 (default 16-bit) > unmaskirq = 0 (off) > using_dma = 0 (off) > keepsettings = 0 (off) > readonly = 0 (off) > readahead = 256 (on) > HDIO_GETGEO failed: Inappropriate ioctl for device > > > When I try to enable DMA using hdparm, I get: > [root@sf002698 ~]# hdparm -d1 /dev/dvd > > /dev/dvd: > setting using_dma to 1 (on) > HDIO_SET_DMA failed: Operation not permitted > using_dma = 0 (off) > > > Checking the config file for the stock kernel installed in these machines, I > see: > [marcelo.sales@sf002698 ~]$ grep _BLK_ /boot/config-$(uname -r) | grep SATA > # CONFIG_BLK_DEV_IDE_SATA is not set > > I assume this is the reason why I can't turn on DMA, am I right? I believe > many, many people shall suffer from this problem too. Should I open an RFE > asking to enable this in the next kernel or is there a specific reason for > not enabling this in the stock kernels? I hope I'll not need to recompile the > kernel and install it in all these machines just because of this :) Please do. To get good performance I have to add the following to the boot kernel parameters: combined_mode=libata atapi_enabled=1 But the DMA is still not activated, however I can watch DVDs & burn cd/dvds ok. -- Brian Millett - [ G'Kar, "The War Prayer"] "So much for Babylon 5's highly vaunted justice."
