Hello, On Thu, 25 May 2006 09:43:39 -0500 Brian Millett <bmillett@xxxxxxxxx> wrote: > 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. Here I added hdc=noprobe to the kernel boot options (grub). Regards, -- wwp
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