Welcome to our peer-to-peer forums, where owners help owners. Need help now? Visit eSupport here.

English Community

Linux Operating SystemsOther Linux Discussions
All Forum Topics
Options

86 Posts

09-08-2016

United States of America

52 Signins

2661 Page Views

  • Posts: 86
  • Registered: ‎09-08-2016
  • Location: United States of America
  • Views: 2661
  • Message 281 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-23, 20:21 PM

Could be. It would be easy for a detail like that to get lost in translation. :(

Reply
Options

86 Posts

09-08-2016

United States of America

52 Signins

2661 Page Views

  • Posts: 86
  • Registered: ‎09-08-2016
  • Location: United States of America
  • Views: 2661
  • Message 282 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-23, 21:57 PM

Someone asked about the idea to kick the hardware into AHCI mode using the Linux kernel on Reddit, so I replied:

 

The beauty of the idea to have Linux kick the machine into AHCI after GRUB starts the kernel is that it gets reset on every boot, and then goes into AHCI mode again when you select Linux.

 

When you select Windows, it will be in the fake RAID mode and you still get full power management, and you won't even have to install Windows again to avoid BSoDs.

 

And there's nothing Lenovo can do about it since we'd only be using their stupid BIOS to bring the machine up and then throwing out their RAID mode once Linux takes over. As long as you don't get a BIOS update that breaks something else. A BIOS update could break Linux again if Lenovo really intended it to, but I'm thinking after being embroiled in a scandal, they won't try this again. Once is a mistake, twice is a habit. You know? That's my opinion.

 

Hopefully once we have an interim fix in place that lets us boot Linux, someone can add support for Lenovo's fake RAID mode and Intel's undocumented power management later, remove the quirk, and we get full power management back. Until then, maybe you get 9 hours instead of 10 on a charge. I haven't tested so I don't know. I would accept the hit to get away from Windows 10, even if we never figure out a solution that lets us run in the RAID mode and support Intel's undocumented power management.

 

Either way, it's what's going to end up "Solving" this thread. Not Lenovo's press release where they were going out of their way to make vomit-inducing endorsements of Windows 10.

Reply
Options

6 Posts

08-13-2016

Brazil

39 Signins

176 Page Views

  • Posts: 6
  • Registered: ‎08-13-2016
  • Location: Brazil
  • Views: 176
  • Message 283 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-23, 22:11 PM
Very nice explanation! I know nothing about the kernel but now I see a light...

Hoping to see it become real so that annoying green "Solved" will mean something.
Reply
Options

86 Posts

09-08-2016

United States of America

52 Signins

2661 Page Views

  • Posts: 86
  • Registered: ‎09-08-2016
  • Location: United States of America
  • Views: 2661
  • Message 284 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-23, 22:44 PM

Running the blockade and accepting that we'll lose some power efficiency in AHCI mode is easier than standing around trying to fight when Lenovo, Microsoft, and Intel have collaborated to force the fake RAID mode and not release power management specs. If the kernel people ever reverse engineer the power management or get specs from Intel, we might be able to have better power management later. Right now, it's probably like 3-4 lines of code in the right place to ditch the RAID mode at boot and run Linux in AHCI anyway (Like Dell XPS laptops have to be configured in their BIOS when you want to install Linux. At least Dell gave their users a choice. Lenovo didn't.). The big downside is that it takes a patch a while to trickle down to the distributions. Someone should ask Fedora to merge the patch as soon as it is written and then to rollup the new kernel into updated installation media. That would probably be the fastest way to get it out to the users. But that's putting the cart before the horse. For now, we're waiting for Matthew Garrett to decide if it can even be done. It likely can. It's probably something that Lenovo was never expecting when they wrote the lockout code for their BIOS.

 

The patch might benefit Dell XPS owners too, since it will let them run Linux in AHCI and Windows in RAID without them ever having to touch the BIOS, or run Windows in AHCI (which loses power efficiency and requires a reinstall to get it to stop crashing).

Reply
Options

15 Posts

07-11-2016

United States of America

151 Signins

1692 Page Views

  • Posts: 15
  • Registered: ‎07-11-2016
  • Location: United States of America
  • Views: 1692
  • Message 285 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-24, 3:49 AM

Let's get to it. Losing a bit of power efficiency is a small price for our mistake of purchasing a wrong product as compared to what Lenovo will eventually pay for their wrong decisions.

Reply
Options

15 Posts

07-11-2016

United States of America

151 Signins

1692 Page Views

  • Posts: 15
  • Registered: ‎07-11-2016
  • Location: United States of America
  • Views: 1692
  • Message 286 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-24, 4:17 AM

wrote:

Right now, it's probably like 3-4 lines of code in the right place to ditch the RAID mode at boot and run Linux in AHCI anyway

 


 

Does anybody know what actual code should look like? As i have working Ubuntu installation on Ideapad 710s that boots from MicroSD I can create a patch for latest Ubuntu and test it before we contact maintainers.

Reply
Options

86 Posts

09-08-2016

United States of America

52 Signins

2661 Page Views

  • Posts: 86
  • Registered: ‎09-08-2016
  • Location: United States of America
  • Views: 2661
  • Message 287 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-24, 9:23 AM

https://mjg59.dreamwidth.org/44694.html

 

You could contact Matthew Garrett there. He would know.

 

He blames Intel. I blame Windows for not having manual driver override support like Linux does. If Windows had this then there would be no need to set the hardware into RAID mode to make sure it doesn't use the generic Windows driver. But it's Microsoft, so all sorts of stupid things happen.

 

Regardless, he's in a position to help us here.

Reply
Options

86 Posts

09-08-2016

United States of America

52 Signins

2661 Page Views

  • Posts: 86
  • Registered: ‎09-08-2016
  • Location: United States of America
  • Views: 2661
  • Message 288 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-24, 9:40 AM

https://mjg59.dreamwidth.org/34868.html

 

I went back and read Matthew Garrett's post from April regarding power management on Haswell and Broadwell, and it explains the mess this new mobile hardware would be in without Intel's RST power management policy.

 

In the past, the power policy for storage controllers apparently didn't matter very much, but now several components are all in the CPU package on Intel's mobile platforms, and so you have to care about the power state of everything, or else nothing gets to go to power save mode.

 

He said he wrote some patches to implement the same policy that Intel RST does, so I haven't had a chance to ask what the situation with Skylake is, but now I at least know more about what we're dealing with. Going from the power management policy of Windows or Linux to the one Windows gets when you load the RST driver, you go from idling at 8.5 watts to about 5, which extends battery life by maybe a couple of hours.

 

The problem with Windows that made Lenovo default to RAID mode is that in RAID mode, Windows basically says "Well, the generic AHCI driver won't work. Better look for another one.", so it loads Intel's RST driver.

 

So it's basically a really ugly kludge to get around the fact that Windows is not a modern operating system with proper manual driver override support. So I get the default, but Lenovo taking away AHCI mode is unforgivable.

 

Power policy and storage controller mode should be otherwise unrelated, really, in that if we manage to get a patch in Linux to kick the storage controller to AHCI native mode after the BIOS exits, Linux developers and distributions could later implement aggressive power saving mode even without the device in the fake RAID configuration.

Reply
Options

15 Posts

08-20-2016

Australia

56 Signins

446 Page Views

  • Posts: 15
  • Registered: ‎08-20-2016
  • Location: Australia
  • Views: 446
  • Message 289 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-24, 11:51 AM

Matthew's stuff about the PCH power states is interesting.  Taking his numbers (which might not be for Skylake) the change in 'idle time' for a 66Wh battery (like in the Yoga 900) between 5W and 8.5W is 13.2 hours and 7.7 hours.  Going to go out on a limb here and say that Skylake is probably more efficient.

Any activity on the machine will of course make it use more power.

 

I've had mine running all week with Ubuntu and off the charger for several days... so sleep works obviously.  I'm not noticing any thermal issues which would worry me more.  I'm about to start compiling kernels on it so we'll see how that goes... if anything is going to push the thermal management it's that.

 

I guess what annoys me about all of this is that Lenovo could have just stated this up front; made the patched BIOS available and with the disclaimer it might negatively affect battery performance and cause more thermal throttling.  I would be perfectly happy with that... I don't do many eight hour solid sessions on a laptop away from power. YMMV.

 

What's more annoying is that if you go and read the Intel forums they say go and talk to the Linux kernel developers... and then the kernel developers say Intel doesn't provide the details. Intel have been doing some great work with Linux lately but obviously this isn't one of those areas...

Reply
Options

6489 Posts

06-27-2008

United States of America

28957 Signins

1658793 Page Views

  • Posts: 6489
  • Registered: ‎06-27-2008
  • Location: United States of America
  • Views: 1658793
  • Message 290 of 394

Re: Yoga 900-13ISK2 - BIOS update for setting RAID mode for missing hard drive on linux install

2016-09-24, 15:49 PM

Moderator comment: A post which did not conform with the Community Rules has been removed. No campaigning.


Community GuidelinesPrivate MessagingENDEESPTRUUACZ-SKTRMoto
Requests for individual support are not answered. If a post solves your issue, please mark it so.

I am not a Lenovo employee

Reply
Forum Home

Community Guidelines

Please review our Guidelines before posting.

Learn More

Check out current deals!

Go Shop
X

Save

X

Delete

X

No, I don’t want to share ideas Yes, I agree to these terms