Subject: Re: Regression in b43 with BCM4311/2
From: Johannes Berg <johannes@sipsolutions.net>
To: Larry Finger <Larry.Finger@lwfinger.net>
Cc: wireless <linux-wireless@vger.kernel.org>
In-Reply-To: <4B65D51F.1090903@lwfinger.net>
References: <4B64A2F2.6060608@lwfinger.net>
	 <1264887027.3546.207.camel@johannes.local> <4B64AAEB.9020806@lwfinger.net>
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Date: Sun, 31 Jan 2010 20:53:14 +0100
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Larry,

> I finally sorted this out. The patch in question (c7ab5ef) is the bad one=
, but
> not the basic response rate part.
>=20
> Going back to the code that worked, I discovered that the routines
> b43_short_slot_timing_enable/disable() were never called. Once the new co=
de
> touched the shared memory location 0x0010, the transmit performance dropp=
ed way
> off. If I let the new code adjust the Interframe Slot time in MMIO space,=
 but
> not the shared memory location, the transmit rate in my BCM4311/2 went fr=
om a
> maximum of 18 to 22 Mb/s. This problem did not affect the 0x4315 device a=
s the
> memory was changed only for G PHYs. I think that should be for 2GHz, and =
have
> made that adjustment. I have not yet tested that with the LP PHY. Once I =
do, I
> will post a patch for comment and testing.

Cool, thanks for looking into it and the detailed analysis!

> Thanks for helping me understand the basic response rates.

Any time.

johannes

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