Re: [PATCH 1/3] Make the IDE DMA timeout modifiable

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Hello.

Bartlomiej Zolnierkiewicz wrote:

On Feb 20, 2007, at 5:44 PM, Bartlomiej Zolnierkiewicz wrote:

On Wednesday 21 February 2007 02:19, Suleiman Souhlal wrote:

It can be changed via /proc/ide/hd?/settings.

Why do we need to change IDE DMA timeout dynamically?

I've used it to test error recovery (for example).

Seems quite useable for developers but I would prefer not to
expose it in production kernels for end users.

It seems that I have counter example of a customer asking if this timeout can be done configurable. :-)

May I ask what was the rationale for this request?

Their system seems to become unschedulable for this period of time (DMA timeouts happen from time to time) -- at least the keepalive daemon stopped replying during this period...

I have no strong feelings about adding this /proc/ide/ setting but I worry
that it could be (mis)used just to (unreliably) work-around problems...

BTW, why the timeout is so damn long? 2*WAIT_CMD is 20 secs, and if DMA is not complete or interrupt pending, it may wait 10 more secs...

I really don't remember... :)

Maybe Mark or Alan could help with figuring this out.

   They also have probably forgotten. :-)

Thanks,
Bart

MBR, Sergei
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