lkml.org 
[lkml]   [2008]   [May]   [31]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateSat, 31 May 2008 11:02:54 +0200
FromBrice Goglin <>
Subjecthowto use ioremap_wc?
Hello,

We're looking at using ioremap_wc() in myri10ge. No drivers seem to be
using it yet, so I'd like to get some clarification regarding ioremap_wc
failures, MTRR and so on.

What we currently do is mtrr_add() and then ioremap. Depending on the
mtrr_add() success, we use the "wc_fifo" or regular PIO with fences to
submit requests to the NIC. How are we supposed to switch this to
ioremap_wc?

Are we sure that if the arch supports _wc, it does not return success
when the underlying plain ioremap worked but setting up _wc() failed? If
so, why does it revert to ioremap_nocache when PAT isn't enabled?

Can we keep the mtrr_add() in the regular path? Or are we supposed to
drop it when the arch provides ioremap_wc and it did not fail?

thanks,
Brice



\
 
 \ /
  Last update: 2008-05-31 11:05    [from the cache]
©2003-2008