From: "John W. Linville" <linville@tuxdriver.com>
To: Claudio Matsuoka <claudio@mandriva.com>
Cc: linux-wireless@vger.kernel.org, flamingice@souremilk.net,
dsd@gentoo.org, kune@deine-taler.de
Subject: Re: RTL8187 rate control problems
Date: Tue, 6 Nov 2007 11:41:48 -0500 [thread overview]
Message-ID: <20071106164148.GB4440@tuxdriver.com> (raw)
In-Reply-To: <200711061323.16302.claudio@mandriva.com>
On Tue, Nov 06, 2007 at 01:23:16PM -0200, Claudio Matsuoka wrote:
> I've been reported a problem with RTL8187 working only at very close ranges
> (4-5m) in Linux while the same hardware works at much higher distances in
> Windows. Investigating the problem, I found that it's caused by the mac80211
> rate control incrementing the bit rate to 54M and never going down because
> the fail counter stays at zero. What would be a good way to check
> transmission retries or failures in the RTL8187 to prevent this problem? Is
> it possible to have a retry count sent to the tx callback so
> status->retry_count could be set accordingly?
I think you are right -- it looks like rtl8187 never sets
excessive_retries for transmit status. I don't see anything obvious
in the specs that would give us an actual indication of that either,
which probably explains why it is missing.
The zd1211rw(-mac80211) driver(s) have a mechanism for matching-up
received ACKs with transmitted frames so that they can synthesize the
required excessive_retries data. Probably rtl8186 needs something
similar. Maybe this would even be worth generalizing?
John
--
John W. Linville
linville@tuxdriver.com
next prev parent reply other threads:[~2007-11-06 16:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-06 15:23 RTL8187 rate control problems Claudio Matsuoka
2007-11-06 16:41 ` John W. Linville [this message]
2007-11-06 16:47 ` John W. Linville
2007-11-06 18:37 ` Michael Wu
2007-11-07 0:39 ` Claudio Matsuoka
2007-11-07 0:47 ` Michael Wu
2007-11-07 14:20 ` Johannes Berg
2007-11-09 11:13 ` Claudio Matsuoka
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