Re: CMD64x IDE driver and DMA [was: Re: Installation Failing Sun V100]
Dear Listmembers,
dear Jurij,
I see the problem with knowing about what DMA mode seems acceptable, this is
an issue when limiting the boot-up dma speed. What seems possible to me is a
list of machines (because I think this problem mainly hurts older systems and
therefore it should be fairly easy to figure out what is the system name and
derive a setting from that).
Who builds the installer should simply be able to add a commandline ide=nodma
to the boot kernel (as SuSE did). One of the first scripts processed after
boot (anything out of /etc/init.d, preferably the script that comes with
hdparm) could be used to perform a setting (see above, /sbin/hdparm -d1
-Xudma2 /dev/hdX for example). Because I think it is mainly an issue related
to the sparc and not to the controller (as they are capable of handling high
speed on i386 architecture) I cannot judge whether this is a linux kernel
problem or a hardware limitation issue.
My arguing is only based on the fact that the main target ought to be
stability, rather than maximum speed for the installation. Who wants to play
- let him play, everybody who wants to do so can set the dma mode to whatever
he wants - at his own risk.
But for the straightforward installation I personally prefer the conservative
way.
I cannot tell about the performance of the 2.6 kernel because I hardly have
access to test hardware but mainly to hardware that is used for production
usage.
For 2.4 @ U60 SMP the maximum was udma2 in conjunction with the promise
controllers (no difference between the two types I tested, one U100, one
U133, udma2 at max, everything faster results in file system corruption)
If there is any additional information I could supply - please give me a note.
Take care
Dieter
Am Donnerstag, 6. Januar 2005 17:25 schrieb Jurij Smakov:
> seen
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