lkml.org 
[lkml]   [2004]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: ide-cd problem
Alan Chandler wrote:
> On Tuesday 23 November 2004 21:49, Alan Chandler wrote:
>
>
>>Before, I thought my hardware was a little out of spec - now I think there
>>is something else at play here.
>>
>
>
> Firstly, I think there might be another race condition like the one Alan Cox
> found. I attach a patch below with the fix for that (against 2.6.10-rc2, an
> including Alan's patch) I'm not 100% sure its necessary, but it seems fix a
> variation I have been seeing.
>
> With it in place, and apart from the ongoing issue - see below, I have managed
> to remove the delay in drive_is_ready() altogether without any ill effects.
>
> [my reading of the ATA spec is that 400ns is needed after reading the status
> reg before IRQ is removed, I had wondered whether it would be better to
> record the time here and then check whether we had used up the 400ns just
> before returning from the interrupt state]

The method is sound, I did some industrial control in a previous job and
used a back-to-back timer in a similar way. Just before starting an
operation I checked to see that it wasn't too soon and did a delay if so.

Depending on the path through the code, it may be easier to get right by
just putting in the delay.

--
-bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:08    [W:0.122 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site