CDROM/DVDROM drives on SATA IDE = no DMA
Marcelo Magno T. Sales
marcelo.sales at sefaz.pe.gov.br
Thu May 25 12:14:07 UTC 2006
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 at 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 at 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 at 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 :)
Thanks,
Marcelo
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