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edub n00b
Joined: 01 Jul 2002 Posts: 17
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Posted: Wed Jul 24, 2002 11:52 am Post subject: idebus= parameter |
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Hi folks,
Have done some searches on this parameter and also some kernel doc reading, and still looking for an answer to my question....which is: I think my bus speed is 133...the highest speed I can specify using this parameter is 66? (i.e., idebus=66).
Am I misunderstanding how this parameter works? Pointers to docs about this would be appreciated along with thoughts on the matter.
Thanks alot,
E |
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Moon n00b
Joined: 14 Jul 2002 Posts: 5
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Posted: Wed Jul 24, 2002 2:18 pm Post subject: |
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If i'm not mistaken the message at boot time
says it assumes IDEBUS=xxx for PIO-Modes,
since you're most likely running with DMA enabled this setting should have no effect.
Moon |
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Moon n00b
Joined: 14 Jul 2002 Posts: 5
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Posted: Wed Jul 24, 2002 2:19 pm Post subject: |
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If i'm not mistaken the message at boot time
says it assumes IDEBUS=xxx for PIO-Modes,
since you're most likely running with DMA enabled this setting should have no effect.
Moon |
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edub n00b
Joined: 01 Jul 2002 Posts: 17
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Posted: Wed Jul 24, 2002 3:13 pm Post subject: |
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DMA gets disabled during boot for whatever reason, so I turn it on via a local.start (i think that's the filename) instruction, which results in successfully turning it on for my drive. However, if I do not specify idebus=66 (the highest setting available for the idebus= parameter), I agree that dmsg says "assuming idebus=33". Setting the idebus=66 param at boot time improves this to an idebus speed of 66, which is good, but not as good as 133. Am I missing something that DMA does to improve this itself? Perhaps turning on DMA improves the bus speed over and above the 66 set by the kernel at boot?
Thanks for the help!
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rommel Veteran
Joined: 19 Apr 2002 Posts: 1145 Location: Williamsburg Virginia
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Posted: Wed Jul 24, 2002 3:32 pm Post subject: |
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what chipset do you have on your mainboard, and did you enable any support for it in the kernel? |
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Hypnos Advocate
Joined: 18 Jul 2002 Posts: 2889 Location: Omnipresent
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Posted: Wed Jul 24, 2002 3:44 pm Post subject: |
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Try benchmarking both options using "hdparm -Tt". I have found that the idebus parameters has zero effect once the kernel is using DMA with the disk. |
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edub n00b
Joined: 01 Jul 2002 Posts: 17
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Posted: Thu Jul 25, 2002 11:17 am Post subject: |
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Thanks for the thoughts, rommel & Hypnos. I will do some further reseach and post here with anything notable. Thanks again. |
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