What is the max power for my card?

Jouni Malinen jkmaline
Sun Jan 19 19:30:56 PST 2003

On Mon, Jan 20, 2003 at 02:11:47AM +0000, wlan wrote:

> Hostap is the only driver that it is not able to know the maximum
> transmit power, or it is common missing feature of all linux drivers?

As far as I know, it is common to all Prism2 drivers, no matter which
OS. Manufacturers could of course hard code the value if they have own
driver versions, but I do not know any generic method of finding this

> So i understand that this behaviour is due to the reason than we don't
> know the maximum value, in such a case won't be better to use
> percentages and change iwconfig man page?

Yes, it would probably be less confusing to use some raw value or
percentage etc. However, it is not enough to just change man pages; this
would need to be implemented first.. ;-)

The value I use in TX power configuration seems to be logarithmic with
most cards, so using dBm has its benifits. Anyway, I would rather start
by reimplementing TX power setting using two BBP registers (one to set
power level and another to give some measurements from the sent frames).
This is the recommended method for host-based TX power controlling, but
I haven't so far tested whether it works as expected.

Jouni Malinen                                            PGP id EFC895FA

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