On Wednesday 10 September 2008 21:42:57 Francesco Gringoli wrote:
> Hello everybody,
>
> we found a strange behavior problem with the b43 driver. We begin
> investigating this when doing some access tests with several boards:
> we discovered that the Broadcom boards usually acquire the channel
> usage with higher priority when the b43 driver is used as respect to
> other vendor boards.
>
> After investigating we saw that the intra-queue contention procedure
> is carried out by the firmware which stores information, such as AIFS
> and current backoffs for each queue, inside the shared memory. The
> AIFS for each queue is used to compute the initial backoff so that
> internal contention usually gives more priority to VO queue (smallest
> AIFS) and less to background (biggest AIFS). AIFS parameters are
> initialized by the driver which is told to use a 22 words long
> structures. The firmware instead use 16 words structures: this means
> that AIFS parameters initialized by the driver do not match the
> corresponding values read by the firmware. We saw that the firmware
> reads (2,0,0,0) instead of (2,2,3,7) which results in very short
> backoff procedures.
>
> Has anyone noticed similar behavior? For the sake of clarity, I'm
> referring to latest (30 minutes ago) version of wireless-git and
> broadcom-wl-4.150.10.5 driver version. I verified that all ucode5.s,
> ucode9.s, ucode11.s, ucode13.s and ucode14.s firmwares use 16 words
> structures, and the driver instead still uses 22 words long
> structures. Probably the attached patch sorts out the problem.
>
> I also noticed that the specs say that these structures are 16 words:
> could not someone read 16 as 0x16 that finally became 0x16 = 22?
The specs are ambiguous here.
The specs table for QoS clearly has 0x16 fields. So I implemented it
this way and read the "foobar has 16 words" text in hex.
"How many people can read hex, if only you and dead people can read hex?" ;)
> --- b43.h.old 2008-09-10 21:12:59.000000000 +0200
> +++ b43.h 2008-09-10 21:13:09.000000000 +0200
> @@ -569,7 +569,7 @@
> #define B43_QOS_VOICE B43_QOS_PARAMS(3)
>
> /* QOS parameter hardware data structure offsets. */
> -#define B43_NR_QOSPARAMS 22
> +#define B43_NR_QOSPARAMS 16
> enum {
> B43_QOSPARAM_TXOP = 0,
> B43_QOSPARAM_CWMIN,
PS: Can you please avoid starting yet another thread for the topic?
We already have one.
Please, guys, keep _threads_. It's important to _not_ start new threads
all the time, so email archive searching is made possible. This is _also_
the case for private mail from you.
You're not the only one in my inbox, but every time I have to search for
your old mail it's a headache.
So good subjects (this one is _not_ a good one) and not breaking threads
is very important.
--
Greetings Michael.
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