Problems with scsi emulation
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I'm using a customized 2.4.20 kernel (red hat 9) with scsi emulation, scsi cdrom & scsi generic support options enabled in .config and hdx-ide-scsi in lilo.conf. apps as cdrecord or cdrdao take up all my cpu time (I have a duron 1.1 gz, kt133, 192mb sdram, 30 gb 5400 rpm hd). in windows (with dma enabled) Nero d oesn't take up any (or almost) cpu time...
is this an issue of the linux-kernel or a configuration problem?
Due to many problems with DMA locking up on ATAPI writers earlier in the lk 2.4 series, Linux takes a very conservative approach and turns off DMA.
It can be turned back on with:
# hdparm -d 1 /dev/hdb assuming your cdwriter is found at /dev/hdb (even though the ide-scsi driver "owns" that device and you address it as /dev/scd0 ). You can get faster DMA modes with the addition of the "-X" switch in hdparm but that should not be necessary.
Doug Gilbert
Quoted 15 lines
Quoted 10 lines
I'm using a customized 2.4.20 kernel (red hat 9) with scsi emulation, scsi cdrom & scsi generic support options enabled in .config and hdx-ide-scsi in lilo.conf. apps as cdrecord or cdrdao take up all my cpu time (I have a duron 1.1 gz, kt133, 192mb sdram, 30 gb 5400 rpm hd). in windows (with dma enabled) Nero d oesn't take up any (or almost) cpu time...
is this an issue of the linux-kernel or a configuration problem?Due to many problems with DMA locking up on ATAPI writers earlier in the lk 2.4 series, Linux takes a very conservative approach and turns off DMA.
It can be turned back on with:
Quoted 7 lines
# hdparm -d 1 /dev/hdb assuming your cdwriter is found at /dev/hdb (even though the ide-scsi driver "owns" that device and you address it as /dev/scd0 ). You can get faster DMA modes with the addition of the "-X" switch in hdparm but that should not be necessary.
Doug:
I've tried that, but it doesn't make any difference.
I've been able to do ficticious tweaks on /dev/hdc and hdd like, for example, activating dma mode 5 -which is virually impossible for a cdrom drive. Actually, as I'd disabled ide/atapi-cdrom support in the kernel I guess that /dev/hdc & hdd point to 'nowhere'. Anyway, with hdparm optimizations or without them processor time consumption remains at a 70 - 90 % so, clearly, I haven't made any progress.
The only interface for cdrom drives that i've enabled in the kernel is scsi (to be able to record and rip w/ cdrdao). I guess that the inability to use dma is related to that because my ide hard disks seem to be using it w/o problems (and obviously I'm not using scsi with them). Nevertheless, I can't set up a multcount higher than 8, which is really surprising because the ide chipset and the drives are quite new.
So I repeat my enquiry, Is all this a question configuration or of a kernel upgrade? I've already tried the latter, but, as far as I could appreciate, the current nvidia 'accelerated' drivers (1.0-4363) for my geforce2 didn't work with the 2.5 kernel (more precisely 2.5.69) I'd compiled. Once more, is this incompatibility a current issue of these kernels? In case it were an configuration error I would certainly do the upgrade because 2.5 kernel series seem to have many advantages, as for example, the inclusion of the alsa sound drivers.
Agustín Herrera
PD: I've changed my adress to [email protected]