Hello.
This is odd. Since 2.4.21-pre5 I can't enable dma for my cd-rom drive. (I haven't checked pre1-pre4) This only happens when ide-scsi is been loaded. If I'm using "the normal" ide-cd everything works fine.
When loading ide-scsi, linux explicitely disables dma:
kernel: SCSI subsystem driver Revision: 1.00
kernel: hdb: attached ide-scsi driver.
kernel: hdb: DMA disabled
kernel: hdd: attached ide-scsi driver.
kernel: hdd: DMA disabled
kernel: scsi0 : SCSI host adapter emulation for IDE ATAPI devices
kernel: Vendor: COMPAQ Model: CD-ROM LTN485 Rev: KQA4
kernel: Type: CD-ROM ANSI SCSI revision: 02
kernel: Vendor: HP Model: CD-Writer+ 9100b Rev: 1.06
kernel: Type: CD-ROM ANSI SCSI revision: 02
Why does linux do this ? I digged in the sources but couldn't find any appropiate changes which can cause this behaviour.
# hdparm -d1 /dev/hdb
/dev/hdb:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma = 0 (off)
However with ide-cd everything works as expected:
kernel: hdb: attached ide-cdrom driver.
kernel: hdb: ATAPI 48X CD-ROM drive, 120kB Cache
kernel: hdd: attached ide-cdrom driver.
kernel: hdd: ATAPI 32X CD-ROM CD-R/RW drive, 2048kB Cache
Copying with ide-cd is significantly faster and consumes less cpu load (dma enabled), but with ide-scsi it is slow (700 KB/s) like pio/4.
Any clues ?
# hdparm -i /dev/hdb
/dev/hdb:
Model=LTN485, FwRev=KQA4, SerialNo=
Config={ SpinMotCtl Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=0kB, 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
AdvancedPM=no
# hdparm -i /dev/hdd
/dev/hdd:
Model=Hewlett-Packard CD-Writer Plus 9100b, FwRev=1.06, SerialNo=
Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=0kB, 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
AdvancedPM=no
$ lspci
00:00.0 Host bridge: Intel Corp. 440BX/ZX - 82443BX/ZX Host bridge (rev 03)
00:01.0 PCI bridge: Intel Corp. 440BX/ZX - 82443BX/ZX AGP bridge (rev 03)
00:0e.0 Ethernet controller: 3Com Corporation 3c905B 100BaseTX [Cyclone] (rev 24)
00:0f.0 Multimedia audio controller: Ensoniq ES1371 [AudioPCI-97] (rev 06)
00:10.0 Multimedia video controller: Brooktree Corporation Bt878 (rev 11)
00:10.1 Multimedia controller: Brooktree Corporation Bt878 (rev 11)
00:14.0 ISA bridge: Intel Corp. 82371AB PIIX4 ISA (rev 02)
00:14.1 IDE interface: Intel Corp. 82371AB PIIX4 IDE (rev 01)
00:14.2 USB Controller: Intel Corp. 82371AB PIIX4 USB (rev 01)
00:14.3 Bridge: Intel Corp. 82371AB PIIX4 ACPI (rev 02)
01:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G400 AGP (rev 82)
*Kristian
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This archive was generated by hypermail 2b29 : Wed Apr 23 2003 - 22:00:33 EST