[PATCH v2] give explicit guidance on the use of 64 bit fields

[James Bottomley <jbottomley@odin.com>]

Just saying 64 bit fields may not be atomic is true, but less helpful
than it might be.  Add explicit guidance about what the consequences of
non-atomicity are

Signed-off-by: James Bottomley <JBottomley@Odin.com>

---

v2 replace should with ought to.  I still think this is nuts as we say
"should" in four other places in appendix B alone.

diff --git a/newdevice.tex b/newdevice.tex
index c7e6221..28e1c7b 100644
--- a/newdevice.tex
+++ b/newdevice.tex
@@ -22,8 +22,9 @@ configuration information (the network device does this for filtering,
 otherwise the table in the config space could potentially be very
 large).
 
-Remember that configuration fields over 32 bits wide might not be
-atomically writable by the driver.
+Remember that configuration fields over 32 bits wide might not be atomically
+writable by the driver.  Therefore, no writeable field which triggers an
+action ought to be wider than 32 bits.
 
 \section{What Device Number?}\label{sec:Creating New Device Types / What Device Number?}