736102 - Decide on units for Wifi + MobileConnection signal strength

Status: RESOLVED FIXED

(Core :: DOM: Device Interfaces, defect)

Description

[Blake Kaplan (:mrbkap) (inactive)]

In bug 732982, cjones asked that the signal strength be given in dB (currently easy to do since that's what wpa_supplicant exposes). Right now, we expose a percentage (0-100). We need to decide what to expose.

One idea that cjones mentioned was to always expose a [0,1] normalized relative strength along with the dB, if available. I don't have strong feelings either way, though it seemed to me that the usefulness of dB was limited in most of the cases where we'd be giving this information out. My plan is to raise this question on the webapi list.

Comment 1

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Going to the list is a great idea.

Comment 2

[Philipp von Weitershausen [:philikon]]

In WebMobileConnection (bug 729173, https://wiki.mozilla.org/WebAPI/WebMobileConnection), we're planning on exposing both the raw dBm (signalStrengthDbm) and a [0, 1] linearized value between (signalStrength). I propose doing the same for Wifi.

Comment 3

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Um, sold! ;)

Comment 4

[Blake Kaplan (:mrbkap) (inactive)]

Shian-Yow, would you be willing to write a patch for this?

You'll have to change the ScanResult function to add a signalStrengthDbm property that is the re-adjusted dBm passed in (that is, subtract 256 if the signal strength is greater than 0) and rename signal -> signalStrength.

At the same time, you should probably make the names on the rssi connectionInfo match, so renaming relSignalStrength to signalStrength and renaming signalStrength to signalStrengthDbm. You'll then need to make similar renamings in DOMWifiManager.js as well. Finally, you'll need to rename the properties in nsIWifi.idl.

Comment 5

[Philipp von Weitershausen [:philikon]]

MobileConnection currently mirrors Wifi's convention, so if we change that, we should change it there, too.

Comment 6

[Philipp von Weitershausen [:philikon]]

See https://mxr.mozilla.org/mozilla-central/source/dom/network/interfaces/nsIDOMMobileConnection.idl

Comment 7

[Blake Kaplan (:mrbkap) (inactive)]

Oops. So in that case, all that needs to happen is the first paragraph of comment 4 (with the proper renaming with signal -> relSignalStrength and adding a new signalStrength name).

Comment 8

[Shian-Yow Wu [:swu]]

Yes, I'll take it, and thanks for these information. :)

(In reply to Blake Kaplan (:mrbkap) from comment #4)
> Shian-Yow, would you be willing to write a patch for this?
> 
> You'll have to change the ScanResult function to add a signalStrengthDbm
> property that is the re-adjusted dBm passed in (that is, subtract 256 if the
> signal strength is greater than 0) and rename signal -> signalStrength.
> 
> At the same time, you should probably make the names on the rssi
> connectionInfo match, so renaming relSignalStrength to signalStrength and
> renaming signalStrength to signalStrengthDbm. You'll then need to make
> similar renamings in DOMWifiManager.js as well. Finally, you'll need to
> rename the properties in nsIWifi.idl.

Comment 9

[Shian-Yow Wu [:swu]]

Attachment: Patch for signal strength naming change

Hi Blake,

This patch still follows current definition in nsIWifi.idl.
Please advice, thank you.

Comment 10

[Blake Kaplan (:mrbkap) (inactive)]

Comment on attachment 623308 [details] [diff] [review]
Patch for signal strength naming change

Perfect, thanks.

Comment 11

[Philipp von Weitershausen [:philikon]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/e9472ce37d84

Comment 12

[Philipp von Weitershausen [:philikon]]

Uh, I landed on inbound...

Comment 13

[(no longer active)]

https://hg.mozilla.org/mozilla-central/rev/e9472ce37d84