Hello. Frederik Deweerdt wrote:
Is there any simple way to force the old IDE driver to limit the DMA speed for a particular device?
No, you can only disable DMA totally, and then set the needed speed via hdparm.
I've got a situation where a drive claims to be capable of supporting UDMA/100, but it's in a noisy environment and gets lots of errors at that speed. I'd like to limit it to UDMA/66 or even UDMA/33.
Are you sure that it's all because of the noise and not a cable type misdetection?
The hdparm command should be able to do this but I can't run it until the system has booted, by which time a bunch of CRC and possibly other errors have already occurred. Ideally it should be possible to limit the speed starting as early as device detection, but I can't find any way to do it. Is there support for such a thing or will I have to hack it in?
Does passing ide=nodma at bootime, and then having init set the DMA at the right speed, would work?
ide=nodma is now obsolete -- use ide_core.nodma=<interface>,<device> instead. Read Documentation/ide/ide.txt before advising. ;-)
Regards, Frederik
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