RE: [clarification request] ieee80211_tx_control.pkt_type

2006-08-21 Thread Johannes Berg
On Fri, 2006-08-18 at 09:25 -0700, Simon Barber wrote:
 It might be appropriate to change it from pkt_type to a flag indicating
 that a timestamp should be added at TX time add_timestamp. This may
 well also end up being used for beacons too on hardware where the
 beacons are completely software generated.

I'll leave that to you or Jouni, was merely asking about the uses :)

Thanks,
johannes
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Re: [clarification request] ieee80211_tx_control.pkt_type

2006-08-18 Thread Jouni Malinen
On Fri, Aug 18, 2006 at 01:41:57PM +0200, Johannes Berg wrote:

 I was pondering the ieee80211_tx_control type and don't see anyone using
 the pkt_type field. d80211 makes great effort to have it correct, but no
 driver uses it.
 
 Hence, my question: What is the purpose of this field? Under what
 circumstances would a driver have to know this? Especially considering
 that it's only normal vs. probe response...

Some hardware designs require this configuration for TX frames. It is
used to select whether some of the fields are being filled in hardware
(e.g., timestamp for Probe Response). This would only be needed for AP
mode and IBSS (adhoc), so it is possible that not all low-level dirvers
have yet been implemented to support such operation.

This pkt_type was added at generic 802.11 layer in order to avoid
forcing the low-level driver to even look at the 802.11 header when
queuing the frame for transmission. Taken into account how simple
operation it is to get the type and subtype from the frame control
field, this tx ctrl pkt_type could be removed, if desired. However, it
was added there for a reason.

-- 
Jouni MalinenPGP id EFC895FA
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Re: [clarification request] ieee80211_tx_control.pkt_type

2006-08-18 Thread Johannes Berg
On Fri, 2006-08-18 at 07:33 -0700, Jouni Malinen wrote:

 Some hardware designs require this configuration for TX frames. It is
 used to select whether some of the fields are being filled in hardware
 (e.g., timestamp for Probe Response). 

Ah ok, timestamp makes sense.

 This would only be needed for AP
 mode and IBSS (adhoc), so it is possible that not all low-level dirvers
 have yet been implemented to support such operation.

Right.

 This pkt_type was added at generic 802.11 layer in order to avoid
 forcing the low-level driver to even look at the 802.11 header when
 queuing the frame for transmission. Taken into account how simple
 operation it is to get the type and subtype from the frame control
 field, this tx ctrl pkt_type could be removed, if desired. However, it
 was added there for a reason.

No, that's ok, I was just wondering why it is there at all.

Thanks for clarifying,
johannes
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RE: [clarification request] ieee80211_tx_control.pkt_type

2006-08-18 Thread Simon Barber
It might be appropriate to change it from pkt_type to a flag indicating
that a timestamp should be added at TX time add_timestamp. This may
well also end up being used for beacons too on hardware where the
beacons are completely software generated.

Simon 

-Original Message-
From: Johannes Berg [mailto:[EMAIL PROTECTED] 
Sent: Friday, August 18, 2006 7:51 AM
To: Jouni Malinen
Cc: netdev@vger.kernel.org; Simon Barber; Jiri Benc
Subject: Re: [clarification request] ieee80211_tx_control.pkt_type

On Fri, 2006-08-18 at 07:33 -0700, Jouni Malinen wrote:

 Some hardware designs require this configuration for TX frames. It is 
 used to select whether some of the fields are being filled in hardware

 (e.g., timestamp for Probe Response).

Ah ok, timestamp makes sense.

 This would only be needed for AP
 mode and IBSS (adhoc), so it is possible that not all low-level 
 dirvers have yet been implemented to support such operation.

Right.

 This pkt_type was added at generic 802.11 layer in order to avoid 
 forcing the low-level driver to even look at the 802.11 header when 
 queuing the frame for transmission. Taken into account how simple 
 operation it is to get the type and subtype from the frame control 
 field, this tx ctrl pkt_type could be removed, if desired. However, it

 was added there for a reason.

No, that's ok, I was just wondering why it is there at all.

Thanks for clarifying,
johannes
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