lkml.org 
[lkml]   [2005]   [May]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [rfc/patch] libata -- port configurable delays
Alan Cox wrote:
>>>4) It may be worthwhile to rewrite the loop to check the Status register
>>>_first_, then delay.
>
>
> The 400nS delay after a command is required before status becomes valid.
> This isn't about 'incorrect' devices in the command case. It is about
> strictly correct behaviour and propogation/response times. For the cases
> its not required and you wan to keep PCI load down then checking first
> is clearly logical.

The 400nS delay isn't the one in the loop. I was referring to the other
delay.

Putting the Status register read first will also flush out any posted
writes, before delaying, and potentially exit more rapidly if the device
is immediately ready.

Jeff


-
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: 2005-05-14 01:15    [W:0.041 / U:3.980 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site