[solved] imac runs hotter with Ubuntu 12.04 LTS & other questions

[PartisanEntity]

Hey all,

I installed Ubuntu 12.04 LTS on my iMac (27-inch, mid 2010 model, identifier is 11,3).

So far no show-stoppers but I did notice that the back of the iMac is much hotter when running Ubuntu for several hours compared to when it runs OSX Mountain Lion.

This brings me to my next point, I installed the vanilla Ubuntu 12.04 LTS, but on some sites I was reading they pointed to a version that contains mac related packages.

So my question is what are these mac related packages? Are they worth installing? Anything to do with proper power and fan control on the imac?

Thanks

[rkmugen]

Could you perhaps share the link or links of those sites that you were reading? The phrase "Mac-related" could arbitrarily mean anything, depending on how one looks at it.

[PartisanEntity]

Hi there,

I have seen articles that link to this page for example: http://cdimage.ubuntu.com/releases/12.04/release/

If you scroll down the page for example there is this here "ubuntu-12.04.2-alternate-amd64+mac.iso" - I'm wondering if this .iso has any power management related packages for example, or any other packages that are a must-have for running Ubuntu on an iMac?

[rkmugen]

You said that you already installed 12.04 onto your iMac. Did you apply all the available software updates? If you did, there would be no real reason to download that "ubuntu-12.04.2-alternate-amd64+mac"... at least, not unless you have mistakenly installed the i386 (32-bit) version (i believe your iMac's i3, i5, or i7 chip is 64-bit).

With regards to power management, what control panels/settings does your 12.04 installation currently have? I mean, doesn't your iMac obey your custom power management settings (sleep/hibernation/restart and so on)? And if you were missing any components, related to power-management or otherwise, you could just download it with apt-get.

With regards to your concern about fan speed/temperature, have you seen this article? It refers to Ubuntu 10.04, but I think some fan-control related info is still valid for your 2010 iMac model:
http://www.retroremakes.com/remaketa...10-04-64bit/p1

[buzzingrobot]

Macs have no BIOS, which dates from the earliest PC hardware. They boot in EFI mode. Ubuntu provides, at the page mentioned by PartisanEnvy, two install images. The image that contains "mac" in the file name will boot in BIOS compatibility mode, which is something Apple devised to support booting Windows via its Bootstrap software. The other image includes the ability to boot in EFI mode. Other than than, the content of the images is identical.

Some Mac hardware, especially MacBooks, often contain two graphic cards. OS X switches transparently between them, but Linux is less able to do that. Many folks who run Linux on one of those MacBooks, therefore, use only one of the cards. Typically, an onboard Intel graphic chip -- the cooler chip -- can only seen by Linux of it is installed and booted in EFI mode.

OS X is better at controlling the fans than Linux. Search for a utility called "macfantctld" which may help you here.

When you research using Linux on your iMac, know the machine's exact hardware configuration. I've found much of available help turns out to work on the specific hardware configuration the author used. Apple hardware and firmware varies from model to model, and sometimes within a model release.

[rkmugen]

....

Some Mac hardware, especially MacBooks, often contain two graphic cards. OS X switches transparently between them, but Linux is less able to do that. Many folks who run Linux on one of those MacBooks, therefore, use only one of the cards. Typically, an onboard Intel graphic chip -- the cooler chip -- can only seen by Linux of it is installed and booted in EFI mode.

....

Couldn't an owner of such a setup (TWO graphics cards; or a system with an on-board graphics chipset + a separate graphics card), make use of both cards simultaneously with the appropriate xorg.conf file?

Or in this case, is the goal actually to 'make' Linux behave in such a way as to dynamically swap between graphics chipsets, depending on the user's actual, desired usage at that a given time? Meaning, that if he/she is browsing a simple website that doesn't contain much (or any) graphics demanding stuff, like Wikipedia, the system would switch to the (weaker/less-power-hungry) on-board graphics chipset. And if he/she starts watching streaming media or playing games, the system would either switch to the more powerful ("dedicated") graphics card..... or somehow utilize both graphics card AND on-board graphics?

[buzzingrobot]

Couldn't an owner of such a setup (TWO graphics cards; or a system with an on-board graphics chipset + a separate graphics card), make use of both cards simultaneously with the appropriate xorg.conf file?

Or in this case, is the goal actually to 'make' Linux behave in such a way as to dynamically swap between graphics chipsets...

If you boot Linux in BIOS compatibility mode on one of these MacBooks, it won't know the onboard Intel video GPU is there. It will use the discrete video card.

To use the onboard Intel chip, Linux must boot in EFI mode. On my MacBook, the discrete Radeon card must be disabled before the kernel loads, by adding code to the grub configuration file to emit a string of data to the controlling hardware in the MacBook. . If the Radeon is not disabled, Linux will see and recognize both cards, but only allow use of the Radeon. The Radeon chip must also be disabled each time the machine wakes from a suspend.

OS X uses the Intel chip for non-demanding work, and switches to the Radeon for heavier graphics work. The user has no idea it's happening. Linux has nothing like that.

[PartisanEntity]

I have been monitoring my temps and fan speeds in Mountain Lion and now comparing them to Ubuntu 12.04 LTS. They are almost identical:

Temps:

Core 0: 43C +/-
Core 1: 49C +/-
Core 2: 42C +/-
Core 3: 40C +/-

Fan Speeds:

ODD: 997 RPM +/-
HDD: 1098 RPM +/-
CPU: 939 RPM +/-

(These values are based on pretty much idle usage, I have Firefox, Pidgin, Terminal, Psensor and OwnCloud running)

So all seems fine so far using vanilla Ubuntu 12.04 LTS on the iMac 11,3.

[pindar]

So all seems fine so far using vanilla Ubuntu 12.04 LTS on the iMac 11,3.

That's because you are looking at the wrong readings... The critical temperature is the GPU. You can get it with this command:

sensors | grep TG0d

Under OS X, the radeon card runs around 50 ° C, often lower. In vanilla Ubuntu, temperature goes up into the high 60s, on hot days or when you're doing graphics intensive things into the high 70s. Now some people say that's quite OK and well within the specs of the radeon cards, but the back of the aluminum display feels really hot, and I'm not comfortable with it. After doing some reading on the net, it turns out that the culprit is the open source radeon driver. It doesn't have any power management and always runs the card at maximum performance, which of course makes it hot. It appears that linux kernel 3.11, which is currently under development, will include a whole series of patches which will allow radeon power management (more info in this phoronix article). So what can you do if you don't want these high temperatures? I see three possibilities:

1. Install a 3.11 kernel and try the power management described in the article linked above. A bit convoluted right now because the kernel is still in development, you will have to download the source, apply patches and compile the kernel.
2. Switch to the proprietary drivers (ati fglrx). I have tried this, and it brings the temperature to the same levels as under OS X. The catch: I haven't had any luck with Ubuntu's driver utility (it's called "jockey," I think); I had to download the zip of the latest version from the amd website and install it manually. And this is something you will have to repeat whenever Ubuntu pushes a new kernel version into the updates.
3. You can force the open source driver to run with a lower power profile. Just run these commands:
   

   sudo su
   <enter your password>
   echo "mid" > /sys/class/drm/card0/device/power_profile

   This will make your card run with the predefined "mid" profile. It lowers graphics performance quite a bit (so switching applications via Alt-Tab may be sluggish), but it brings the temperature down to reasonable levels.

For the time being, I use method 3, especially on hot days (as we have had this month in Europe), but I hope saucy includes the 3.11 kernel and the new power management utilities.

[PartisanEntity]

That's because you are looking at the wrong readings... The critical temperature is the GPU. You can get it with this command:

sensors | grep TG0d

Under OS X, the radeon card runs around 50 ° C, often lower. In vanilla Ubuntu, temperature goes up into the high 60s, on hot days or when you're doing graphics intensive things into the high 70s. Now some people say that's quite OK and well within the specs of the radeon cards, but the back of the aluminum display feels really hot, and I'm not comfortable with it. After doing some reading on the net, it turns out that the culprit is the open source radeon driver. It doesn't have any power management and always runs the card at maximum performance, which of course makes it hot. It appears that linux kernel 3.11, which is currently under development, will include a whole series of patches which will allow radeon power management (more info in this phoronix article). So what can you do if you don't want these high temperatures? I see three possibilities:

1. Install a 3.11 kernel and try the power management described in the article linked above. A bit convoluted right now because the kernel is still in development, you will have to download the source, apply patches and compile the kernel.
2. Switch to the proprietary drivers (ati fglrx). I have tried this, and it brings the temperature to the same levels as under OS X. The catch: I haven't had any luck with Ubuntu's driver utility (it's called "jockey," I think); I had to download the zip of the latest version from the amd website and install it manually. And this is something you will have to repeat whenever Ubuntu pushes a new kernel version into the updates.
3. You can force the open source driver to run with a lower power profile. Just run these commands:
   

   sudo su
   <enter your password>
   echo "mid" > /sys/class/drm/card0/device/power_profile

   This will make your card run with the predefined "mid" profile. It lowers graphics performance quite a bit (so switching applications via Alt-Tab may be sluggish), but it brings the temperature down to reasonable levels.

For the time being, I use method 3, especially on hot days (as we have had this month in Europe), but I hope saucy includes the 3.11 kernel and the new power management utilities.

Thanks very much for this. I have been testing it, and it is keeping the temps down. I have been using the "mid" profile.