Hi,
I'm trying to enable DMA (hdparm -d 1 /dev/hdc) for my DVDrw because of
the choppy video image, and I get:
  
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma    =  0 (off)

My system is a Dell Inspiron 6000 running Debian unstable with kernel
version 2.6.12.3 (from kernel.org)

After googling I discovered that the solution for many was changing in
include/linux/libata.h

#undef ATA_ENABLE_ATAPI /* define to enable ATAPI support */ 
to 
#define ATA_ENABLE_ATAPI /* define to enable ATAPI support */

I did this and yet my problem was not solved, I also tried this patch
(as specified in
http://www.mail-archive.com/linux-ide@vger.kernel.org/msg00910.html)
--- drivers/scsi/ata_piix.c.orig        2005-03-17 17:34:45.000000000
-0800
+++ drivers/scsi/ata_piix.c     2005-04-07 18:17:42.287756482 -0700
@@ -46,8 +46,8 @@
        /* combined mode.  if set, PATA is channel 0.
         * if clear, PATA is channel 1.
         */
-       PIIX_COMB_PATA_P0       = (1 << 1),
-       PIIX_COMB               = (1 << 2), /* combined mode enabled? */
+       PIIX_COMB_PATA_P0       = (1 << 0),
+       PIIX_COMB               = (1 << 1), /* combined mode enabled? */
 
        PIIX_PORT_PRESENT       = (1 << 0),
        PIIX_PORT_ENABLED       = (1 << 4),
==== cut here ====


I'm attaching my .conf, lspci -v and dmesg output files, if anyone could tell me what I'm doing wrong I would really appreciate it.
BTW: Please CC any answers to my email because I'm not subscribed to the list.

Thanks in advance,
Dave