8aa3468624
4 Commits
| Author | SHA1 | Message | Date | |
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Adrian Chadd
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22a3aee637 |
Implement my first cut at "correct" node power-save and
PS-POLL support. This implements PS-POLL awareness i nthe * Implement frame "leaking", which allows for a software queue to be scheduled even though it's asleep * Track whether a frame has been leaked or not * Leak out a single non-AMPDU frame when transmitting aggregates * Queue BAR frames if the node is asleep * Direct-dispatch the rest of control and management frames. This allows for things like re-association to occur (which involves sending probe req/resp as well as assoc request/response) when the node is asleep and then tries reassociating. * Limit how many frames can set in the software node queue whilst the node is asleep. net80211 is already buffering frames for us so this is mostly just paranoia. * Add a PS-POLL method which leaks out a frame if there's something in the software queue, else it calls net80211's ps-poll routine. Since the ath PS-POLL routine marks the node as having a single frame to leak, either a software queued frame would leak, OR the next queued frame would leak. The next queued frame could be something from the net80211 power save queue, OR it could be a NULL frame from net80211. TODO: * Don't transmit further BAR frames (eg via a timeout) if the node is currently asleep. Otherwise we may end up exhausting management frames due to the lots of queued BAR frames. I may just undo this bit later on and direct-dispatch BAR frames even if the node is asleep. * It would be nice to burst out a single A-MPDU frame if both ends support this. I may end adding a FreeBSD IE soon to negotiate this power save behaviour. * I should make STAs timeout of power save mode if they've been in power save for more than a handful of seconds. This way cards that get "stuck" in power save mode don't stay there for the "inactivity" timeout in net80211. * Move the queue depth check into the driver layer (ath_start / ath_transmit) rather than doing it in the TX path. * There could be some naughty corner cases with ps-poll leaking. Specifically, if net80211 generates a NULL data frame whilst another transmitter sends a normal data frame out net80211 output / transmit, we need to ensure that the NULL data frame goes out first. This is one of those things that should occur inside the VAP/ic TX lock. Grr, more investigations to do.. Tested: * STA: AR5416, AR9280 * AP: AR5416, AR9280, AR9160 |
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Adrian Chadd
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eb6f0de09d |
Introduce TX aggregation and software TX queue management
for Atheros AR5416 and later wireless devices. This is a very large commit - the complete history can be found in the user/adrian/if_ath_tx branch. Legacy (ie, pre-AR5416) devices also use the per-software TXQ support and (in theory) can support non-aggregation ADDBA sessions. However, the net80211 stack doesn't currently support this. In summary: TX path: * queued frames normally go onto a per-TID, per-node queue * some special frames (eg ADDBA control frames) are thrown directly onto the relevant hardware queue so they can go out before any software queued frames are queued. * Add methods to create, suspend, resume and tear down an aggregation session. * Add in software retransmission of both normal and aggregate frames. * Add in completion handling of aggregate frames, including parsing the block ack bitmap provided by the hardware. * Write an aggregation function which can assemble frames into an aggregate based on the selected rate control and channel configuration. * The per-TID queues are locked based on their target hardware TX queue. This matches what ath9k/atheros does, and thus simplified porting over some of the aggregation logic. * When doing TX aggregation, stick the sequence number allocation in the TX path rather than net80211 TX path, and protect it by the TXQ lock. Rate control: * Delay rate control selection until the frame is about to be queued to the hardware, so retried frames can have their rate control choices changed. Frames with a static rate control selection have that applied before each TX, just to simplify the TX path (ie, not have "static" and "dynamic" rate control special cased.) * Teach ath_rate_sample about aggregates - both completion and errors. * Add an EWMA for tracking what the current "good" MCS rate is based on failure rates. Misc: * Introduce a bunch of dirty hacks and workarounds so TID mapping and net80211 frame inspection can be kept out of the net80211 layer. Because of the way this code works (and it's from Atheros and Linux ath9k), there is a consistent, 1:1 mapping between TID and AC. So we need to ensure that frames going to a specific TID will _always_ end up on the right AC, and vice versa, or the completion/locking will simply get very confused. I plan on addressing this mess in the future. Known issues: * There is no BAR frame transmission just yet. A whole lot of tidying up needs to occur before BAR frame TX can occur in the "correct" place - ie, once the TID TX queue has been drained. * Interface reset/purge/etc results in frames in the TX and RX queues being removed. This creates holes in the sequence numbers being assigned and the TX/RX AMPDU code (on either side) just hangs. * There's no filtered frame support at the present moment, so stations going into power saving mode will simply have a number of frames dropped - likely resulting in a traffic "hang". * Raw frame TX is going to just not function with 11n aggregation. Likely this needs to be modified to always override the sequence number if the frame is going into an aggregation session. However, general raw frame injection currently doesn't work in general in net80211, so let's just ignore this for now until this is sorted out. * HT protection is just not implemented and won't be until the above is sorted out. In addition, the AR5416 has issues RTS protecting large aggregates (anything >8k), so the work around needs to be ported and tested. Thus, this will be put on hold until the above work is complete. * The rate control module 'sample' is the only currently supported module; onoe/amrr haven't been tested and have likely bit rotted a little. I'll follow up with some commits to make them work again for non-11n rates, but they won't be updated to handle 11n and aggregation. If someone wishes to do so then they're welcome to send along patches. * .. and "sample" doesn't really do a good job of 11n TX. Specifically, the metrics used (packet TX time and failure/success rates) isn't as useful for 11n. It's likely that it should be extended to take into account the aggregate throughput possible and then choose a rate which maximises that. Ie, it may be acceptable for a higher MCS rate with a higher failure to be used if it gives a more acceptable throughput/latency then a lower MCS rate @ a lower error rate. Again, patches will be gratefully accepted. Because of this, ATH_ENABLE_11N is still not enabled by default. Sponsored by: Hobnob, Inc. Obtained from: Linux, Atheros |
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Adrian Chadd
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bf26df3693 |
The current code used the fields in ath_set11nratescenario() . Use them
correctly: * pass in whether to allow the hardware to override the duration field in the main data frame (durupdate_en) - PS_POLL frames in particular don't have the duration bit overriden; * there's no rts/cts duration here; that's done elsehwere |
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Adrian Chadd
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4b44f6f275 |
Include some preliminary TX HT rate scenario setup code.
The AR5416 and later TX descriptors have new fields for supporting 11n bits (eg 20/40mhz mode, short/long GI) and enabling/disabling RTS/CTS protection per rate. These functions will be responsible for initialising the TX descriptors for the AR5416 and later chips for both HT and legacy frames. Beacon frames will remain using the non-11n TX descriptor setup for now; Linux ath9k does much the same. Note that these functions aren't yet used anywhere; a few more framework changes are needed before all of the right rate information is available for TX. |