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

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Mark Lord wrote:

>> O> >>    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. :-)

>> Because that value seemed to work ok. Mark set the timeouts way back in
>> history and I never touched most of them.
> 
> 
> I've lost the original question from this thread, but the idea of the 

    The original question concerned specifically the DMA command timeout which 
is twice more than the usual one, WAIT_CMD (10 seconds).

> longish
> timeouts was that drive *may* be spun down ("standby"), and thus have to 
> spin
> up again to complete media commands.  Back then, drives were much slower at
> spinning up than nowadays, and the ATA spec says to allow up to 30 seconds.

    Well, that doesn't explain the DMA case.

MBR, Sergei