Linux Mint 10 - WiFi Transmit Power [Intel 3945 ABG]

[Brian10161]

Well, I have a conundrum. I initally thought changing the palmrest on my X60s was the solution to the hot palmrest. Then I thought it was my removing the WWAN card and associated accessories. Then I thought it was the transition to an SSD (Figured the reduction in heat production, helped the tiny fan overcome the heat and cool down the wifi card).

Now I have determined what it is. WiFi Transmit power and power savings mode. Because my house is fairly small, I'm never more than about 10 - 15 feet from my router (it's in the basement, but sitting on top of a return air duct so it's technically in the ceiling cavity).

I'd like to switch this computer over to Linux Mint 10 (or 9 XFCE) but for the life of me, I can't figure out how to drop the transmit power and ensure power savings is on. Because of this, I have been reluctant to switch to Linux. When I run under Mint, the palmrest gets so darn hot I fear it's cooking the card.

Under XP when I enable Max power savings and drop the TX power down to the bottom, the palmrest stays really cool and my WiFi signal is still good plus TX rates are fine.

Anyway, I was hoping someone here knew how to do this with the Intel 3945 ABG wifi card. I'd appreciate any help!

Thanks guys!

[ThinkRob]

Anyway, I was hoping someone here knew how to do this with the Intel 3945 ABG wifi card. I'd appreciate any help!

There are actually two types of power saving for the iwl3945 driver: normal power saving and transmit power reduction. Now while I know that the former is not possible (it's disabled in the driver due to a hardware bug), you should be able to do the latter via the iwconfig command.

Example:

Code: Select all

iwconfig $interface txpower $value

Where $interface is your wireless interface's name and $value is the transmit power value you want.

[Brian10161]

I will give that a try in the morning, I'm just about ready for bed. Appreciate the response Rob!

[ThinkRob]

I will give that a try in the morning, I'm just about ready for bed. Appreciate the response Rob!

No problem. Just let me know if you need any further help.

(I've got a kernel patch to allow full power saving to be enabled with the iwl3945 driver, but I can't say I recommend it -- the 3945 has some stability issues coming out of suspend when power saving has been enabled. Still, if you want the patch I can post it and/or port it to your kernel of choice.)

[Brian10161]

That did help, but it still doesn't run as cool as it does under XP, so the power savings is the culprit.

I did a little test today with two WiFi cards. I pulled the Atheros card from my T60 and tried it in my X60s. The heat is approximately the same. If anything, the Intel card runs a little cooler because of the power savings feature. Even though I enabled Max power savings on the Atheros card, it still ran hot.

I hooked my Fluke thermometer up and both cards run about 50'C when transmitting data. The Intel card cools to around 38'C when in power savings mode and the Atheros really doesn't drop once it's heated up. Bottomed out at 47'C.

Looks like the Intel card is the one to run in these computers if your trying to keep the heat down. Else, a modded BIOS would be in order, which I am not comfortable doing on a working piece of tech.

Thanks again ThinkRob!

[ThinkRob]

Looks like the Intel card is the one to run in these computers if your trying to keep the heat down. Else, a modded BIOS would be in order, which I am not comfortable doing on a working piece of tech.

Oh, I really wouldn't worry about that. I've flashed tons of ThinkPads, and I've never once had a brick. I had one experience with a T500 where the flash didn't take (i.e. the BIOS didn't change), but that was entirely my fault and it certainly didn't damage anything.

If you do flash, you can upgrade to a 5100 for peanuts (the cards are like $20 on eBay). The 5100/5300 series *does* have power savings enabled in the driver and is (IMHO) a much nicer piece of hardware. Also, you'll be able to use the iwlagn driver which is IIRC a bit more actively maintained.

[Brian10161]

Maybe I will consider flashing the BIOS and using a 5100 card. It looks promising. I don't use Wireless N, my router is a Linksys WRT54G.

Is there a tutorial on how to flash the BIOS in my X60s? Off to search it is I suppose

[Brian10161]

I was wondering if there was a way to make the change permanent. My Asus F8Sn has the same WiFi card in it and I'd like to drop the TX power permanently. When I make the change, it resets after a reboot.

Thanks again!

[ThinkRob]

I was wondering if there was a way to make the change permanent. My Asus F8Sn has the same WiFi card in it and I'd like to drop the TX power permanently. When I make the change, it resets after a reboot.

Add the appropriate command to /etc/rc.local

[Brian10161]

That worked, thanks Rob!