Hi Phoebe, On Mon, Apr 27, 2015 at 01:49:32PM +0200, Phoebe Buckheister wrote: > On Thu, 23 Apr 2015 18:47:48 +0200 > Alexander Aring <alex.aring@xxxxxxxxx> wrote: > ... > > + int (*get_tx_powers)(struct ieee802154_hw > > *hw, s8 *dbm, > > + u32 idx); > > I suggest you use mBm instead of dBm here, while you're at it anyway. > Especially since one of your later patches will add incorrect values > because dBm isn't accurate enough for what the transceiver support > (rf230, TX power +3.4dBm). This would also make the value-2 return you > have right now unnecessary. > The 802.15.4 standard describes in the phy pib for tx power: attr: phyTXPower type: signed integer range: - describtion: The transmit power of the device in dBm. I mentioned in my previous mail that this doesn't repsonse the reality because there are transceivers outside which supports tx power in dbm which are not signed integer, like +3.4 dbm. Nevertheless I would say forget that what the PIB says, we do what the reality does now. (In my previous mail I was another opinion because the current type is s8). I think we should not do that now, because we get trouble later, this is what you mentioned now and I agree. Plan to implement the mbm: 1. change current tx power to S32 instead s8. I gave it a try phy dump with iwpan still works, (not ends in a critical error), so I will change it. 2. the kernelside use mbm everywhere the userspace side kann convert the dbm values to mbm then with a calculation "dbm = mbm / 100" and "mbm = dbm * 100". Some helper marcos like: #define DBM_TO_MBM(gain) ((int)(((float)gain) * 100)) #define MBM_TO_DBM(gain) ((float)(gain) / 100) Examples MBM | DBM +230 | +2.3 -280 | -2.8 ... | .... Thanks, for the review. - Alex -- To unsubscribe from this list: send the line "unsubscribe linux-wpan" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
