[PATCH] mac80211: Extend filter flag documentation about unsupported flags

[PATCH] mac80211: Extend filter flag documentation about unsupported flags

[Michael Buesch]

This extends the filter flags documentation to make it clear
what clearing a flag really means.

Signed-off-by: Michael Buesch <mb@bu3sch.de>

Index: wireless-2.6/include/net/mac80211.h
===================================================================
--- wireless-2.6.orig/include/net/mac80211.h	2008-02-08 22:54:22.000000000 +0100
+++ wireless-2.6/include/net/mac80211.h	2008-02-11 18:22:19.000000000 +0100
@@ -790,14 +790,24 @@ static inline void SET_IEEE80211_PERM_AD
  *
  * If your device has no multicast address filters your driver will
  * need to check both the %FIF_ALLMULTI flag and the @mc_count
  * parameter to see whether multicast frames should be accepted
  * or dropped.
  *
- * All unsupported flags in @total_flags must be cleared, i.e. you
- * should clear all bits except those you honoured.
+ * All unsupported flags in @total_flags must be cleared.
+ * Hardware does not support a flag if it is incapable of _passing_
+ * the frame to the stack. Otherwise it must simply ignore the flag,
+ * but not clear it.
+ * You must _only_ clear the flag (announce no support for the
+ * flag to mac80211) if you are not able to pass the packet type
+ * to the stack (so the hardware always filters it).
+ * So for example, you should clear @FIF_CONTROL, if your hardware
+ * always filters control frames. If your hardware does always pass
+ * control frames to the kernel and is incapable of filtering them,
+ * you do _not_ clear the @FIF_CONTROL flag.
+ * This rule applies to all other FIF flags as well.
  */
 
 /**
  * enum ieee80211_filter_flags - hardware filter flags
  *
  * These flags determine what the filter in hardware should be

Re: [PATCH] mac80211: Extend filter flag documentation about unsupported flags

[Johannes Berg]

[-- Attachment #1: Type: text/plain, Size: 654 bytes --]


> + * All unsupported flags in @total_flags must be cleared.
> + * Hardware does not support a flag if it is incapable of _passing_
> + * the frame to the stack. Otherwise it must simply ignore the flag,
> + * but not clear it.

I think mentioning the driver is important:

"Otherwise the driver must ignore the flag but not clear it."

> + * So for example, you should clear @FIF_CONTROL, if your hardware
> + * always filters control frames. If your hardware does always pass

s/does always pass/always passes/

Other than that,

Acked-by: Johannes Berg <johannes@sipsolutions.net>

so please add that when you resend.

johannes

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 828 bytes --]