I have a problem on which I'm struggling since i started using linux a year ago on my desktop, but still haven't found a solution for it. When reading or burning a dvd, the speeds are very slow (mostly under 1x) whilst I did selected the fastest speed in k3b. As such, it takes up to 40-50 minutes to burn one dvd! I read about enabling dma this post but it didn't help. This is the output for dmesg | grep -i dma

> [    0.000000]   DMA      0x00000010 -> 0x00001000
[    0.000000]   DMA32    0x00001000 -> 0x00100000
[    0.000000]   DMA zone: 56 pages used for memmap
[    0.000000]   DMA zone: 5 pages reserved
[    0.000000]   DMA zone: 3921 pages, LIFO batch:0
[    0.000000]   DMA32 zone: 3527 pages used for memmap
[    0.000000]   DMA32 zone: 254441 pages, LIFO batch:31
[    0.000000] Policy zone: DMA32
[    0.120356] pnp 00:01: [dma 4]
[    0.120968] pnp 00:05: [dma 2]
[    0.121421] pnp 00:06: [dma 3]
[    0.122617] pnp 00:0b: [dma 0 disabled]
[    0.852321] ata1: SATA max UDMA/133 cmd 0xec00 ctl 0xe480 bmdma 0xe000 irq 19
[    0.852325] ata2: SATA max UDMA/133 cmd 0xe400 ctl 0xe080 bmdma 0xe008 irq 19
[    0.861633] ata3: PATA max UDMA/133 cmd 0x1f0 ctl 0x3f6 bmdma 0xff00 irq 14
[    0.861636] ata4: PATA max UDMA/133 cmd 0x170 ctl 0x376 bmdma 0xff08 irq 15
[    1.329411] ata1.00: ATA-7: Maxtor 6V250F0, VA111630, max UDMA/133
[    1.345418] ata1.00: configured for UDMA/133
[    1.820606] ata4.00: ATAPI: PHILIPS DVDR1660P1, P1.3, max UDMA/33
[    1.820610] ata4.00: WARNING: ATAPI DMA disabled for reliability issues.  It can be enabled
[    1.820613] ata4.00: WARNING: via pata_ali.atapi_dma modparam or corresponding sysfs node.
[    1.836681] ata4.00: configured for UDMA/33
[   12.296600] parport0: PC-style at 0x378 (0x778), irq 7, dma 3 [PCSPP,TRISTATE,COMPAT,EPP,ECP,DMA]

reading the third and fourth last line, I assume there is indeed a problem with dma?

edit: this question still is not solved. Could anyone come up with an other solution please? Thanks