I attached a Toshiba DVD-ROM at the ASUS A7V133 Promise controller. The highest transfer mode I can use is Multiword DMA 2, though I activated the DMA-Option in the IDE-kernel configuration. >hdparm -i /dev/hde /dev/hde: Model=TOSHIBA DVD-ROM SD-M1502, FwRev=1008, SerialNo=2100807146 Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic } RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0 BuffType=unknown, BuffSize=128kB, MaxMultSect=0 (maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4 DMA modes: sdma0 sdma1 sdma2 mdma0 mdma1 *mdma2 udma0 udma1 udma2 AdvancedPM=no Drive Supports : ATA/ATAPI-5 T13 1321D revision 3 : ATA-2 ATA-3 ATA-4 ATA-5 If I try >hdparm -d 1 /dev/hde /dev/hde: setting using_dma to 1 (on) using_dma = 1 (on) to active the UDMA-Modes the drive is not accessible. Mount and file access fail, but > hdparm -i /dev/hde /dev/hde: Model=TOSHIBA DVD-ROM SD-M1502, FwRev=1008, SerialNo=2100807146 Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic } RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0 BuffType=unknown, BuffSize=128kB, MaxMultSect=0 (maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4 DMA modes: sdma0 sdma1 sdma2 mdma0 mdma1 *mdma2 udma0 udma1 udma2 AdvancedPM=no Drive Supports : ATA/ATAPI-5 T13 1321D revision 3 : ATA-2 ATA-3 ATA-4 ATA-5 shows no difference. after I tried to access to drive dmesg shows: ISO 9660 Extensions: Microsoft Joliet Level 3 hde: timeout waiting for DMA ide_dmaproc: chipset supported ide_dma_timeout func only: 14 hde: tray open end_request: I/O error, dev 21:00 (hde), sector 112 ISOFS: unable to read i-node block ISOFS: changing to secondary root hde: tray open end_request: I/O error, dev 21:00 (hde), sector 336 ISOFS: unable to read i-node block VFS: Disk change detected on device ide2(33,0) ISO 9660 Extensions: Microsoft Joliet Level 3 ISO 9660 Extensions: RRIP_1991A hde: timeout waiting for DMA ide_dmaproc: chipset supported ide_dma_timeout func only: 14 hde: tray open end_request: I/O error, dev 21:00 (hde), sector 120 But I did not opened the tray. After setting back with hdparm -d 0 the drive is functional again. If I use the VIA-Controller with the same drive I am able to activate udma2 successfully. Any ideas? Thanks my configuration: hda=Maxtor 5T020H2 (VIA) hdc=Maxtor 52049H3 (VIA) hde=TOSHIBA DVD-ROM SD-M1502 (Promise PDC20265) hdg=SONY CD-RW CRX140E with SCSI-Emulation Kernel 2.4.5-ac21. But similar with older Kernels. Mandrake 8.0 >lsmod Module Size Used by NVdriver 658480 15 parport_pc 24144 1 (autoclean) lp 6256 0 (autoclean) parport 27008 1 (autoclean) [parport_pc lp] es1370 26432 1 soundcore 4176 4 [es1370] 3c59x 25440 1 (autoclean) usbmouse 2016 0 (unused) mousedev 4096 1 input 3584 0 [usbmouse mousedev] usb-uhci 21360 0 (unused) usbcore 49152 1 [usbmouse usb-uhci] ide-scsi 7952 0 scsi_mod 54720 1 [ide-scsi] ntfs 49072 1 (autoclean) nls_iso8859-1 2880 3 (autoclean) nls_cp850 3616 2 (autoclean) >lspci 00:00.0 Host bridge: VIA Technologies, Inc.: Unknown device 0305 (rev 03) 00:01.0 PCI bridge: VIA Technologies, Inc.: Unknown device 8305 00:04.0 ISA bridge: VIA Technologies, Inc. VT82C686 [Apollo Super] (rev 40) 00:04.1 IDE interface: VIA Technologies, Inc. VT82C586 IDE [Apollo] (rev 06) 00:04.2 USB Controller: VIA Technologies, Inc. VT82C586B USB (rev 16) 00:04.3 USB Controller: VIA Technologies, Inc. VT82C586B USB (rev 16) 00:04.4 Bridge: VIA Technologies, Inc. VT82C686 [Apollo Super ACPI] (rev 40) 00:0a.0 Multimedia audio controller: Ensoniq ES1370 [AudioPCI] (rev 01) 00:0d.0 Ethernet controller: 3Com Corporation 3c905B 100BaseTX [Cyclone] (rev 30) 00:11.0 Unknown mass storage controller: Promise Technology, Inc.: Unknown device 0d30 (rev 02) 01:00.0 VGA compatible controller: nVidia Corporation NV11 (rev a1) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/