>  Not really, because the linux kernel supports loadable modules. However,
> it does support drivers embedded in the kernel as well.

Yeh I figured that out by the end of reading your post, so what are the pros 
and cons of loadable modules compared to drivers embedded in the kernel?  If 
needing to install an embedded driver requires recompiling the kernel, why 
not just use a module instead - wouldn't it be much quicker to install?

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Jim Henderson wrote:
> On Wed, 10 Dec 2008 16:27:30 -0500, Tom Austin wrote:
> 
>> actually now that I've had more time to think about it, I was actually
>> using initramfs which has settings to build and pack with the kernel
>> image.  Made it very simple indeed.
> 
> Oh, yeah, that definitely would make it simple.  :-)
> 
> Jim

What wasn't simple was figuring out that there was a problem with the 
the baud rate multiplier in my test setup.  I still don't understand 
the origins of it, but with a patch I got the gibberish turned into 
actual text.

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scott wrote:
> 
> Yeh I figured that out by the end of reading your post, so what are the
> pros and cons of loadable modules compared to drivers embedded in the
> kernel?  If needing to install an embedded driver requires recompiling
> the kernel, why not just use a module instead - wouldn't it be much
> quicker to install?
> 

Yes, it is, Module can also be unloaded and reloaded, which usually
leads to resetting the device itself. Therefore jammed device or driver
(module) won't end by the whole computer needing a reboot.

Basically only pro for built-in drivers instead of modules is that they
are automatically available. If you'll eg. compile your SATA-drivers as
module, you'll need to load them before you can find HD's. While the
modules are on the HD, you'll need to get them to memory before that,
which means you'll need to do initrd (or initramrd oslt, which is easier
today IIUC).

So, the easy but still efficient basics: disk and RAID -drivers
built-in, others as module.

-Aero

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Severi Salminen wrote:
> For the record: it takes only 11 seconds for my system to go from Grub
> menu to login (no X at that point). I use Gentoo.

I saw an interesting project where people were figuring out what steps you 
could cut out of a Linux boot for known hardware (like a laptop) to get it 
to boot all the way to logged in under X in less than five seconds. They 
apparently got it working, too.

-- 
   Darren New, San Diego CA, USA (PST)
   The NFL should go international. I'd pay to
   see the Detroit Lions vs the Roman Catholics.

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>> I meant there are no Linux drivers for high-end hardware like expensive
>> graphics cards. Clearly there *are* Linux drivers for lots of other
>> things.
> 
> No Linux drivers for what high-end expensive graphics cards, exactly?  

I didn't say "no", I said "few". And I was making a generalisation.

> Most of those are now Nvidia or ATI IIRC, and there are Linux drivers 
> that support the majority of those cards, even with 3D (though you often 
> have to go to a proprietary kernel module for it).  I use both the ATI 
> and Nvidia drivers, so it's not exactly accurate to say that those cards 
> don't work well with Linux.

Things have improved since 2006 then. ;-) I wasted a whole day trying to 
get the nVidia drivers to work...

(Of course, a few months later I upgraded my graphics card, making my 
Linux partition non-bootable. That was roughly when I decided to just 
not bother fixing it.)

>> And by "a few" I meant more games and applications rather than drivers.
> 
> There's quite a large selection of software.  It may not be WoW, but it's 
> out there.

Sure. And it'll probably continue to get larger over time. But right 
now, it's still fairly modest by comparison.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Darren New wrote:

> I saw an interesting project where people were figuring out what steps 
> you could cut out of a Linux boot for known hardware (like a laptop) to 
> get it to boot all the way to logged in under X in less than five 
> seconds. They apparently got it working, too.

And why shouldn't it boot in 5 seconds flat? Damnit! >_<

It seems that OpenSUSE likes to spend 20 minutes "layout out startup 
files" or something. Very odd... But then, this is from the distro that 
comes with a preconfigured AT job to rebuild the manpages once per day. 
(Um... why?)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Orchid XP v8 wrote:
> And why shouldn't it boot in 5 seconds flat? Damnit! >_<

Some hardware just takes time to initialize and get polled. If you're going 
to support (for example) USB devices, you're going to be slowed down by the 
built-in time delays in the USB standard for initializing devices. I know a 
guy who works on some motherboards they use on big disk-server thingies, and 
it takes seven seconds just to get to the point where the firmware can run, 
simply initializing all the various chips and letting them stablize. They 
axed out starting the mail server, munging the keymaps at start-up, and so on.

I don't remember what it all was, but remember that hard drives, especially 
notebook drives, aren't all that fast, especially when seeking.

Oh, there's the link. Easier to find than I expected. 
http://lwn.net/Articles/299483/

Ah, they're booting off solid state. Hard drives take 10 seconds. They added 
something not unlike MS's "readyboot", which keeps track of the order the 
kernel pages disk pages into memory and uses that next time to read ahead.

I've noticed that even BIOS boot times, a while back, suddenly went way 
down. A few years ago, a BIOS would take 30 or 40 seconds of fiddling around 
to initialize. Then all of a sudden, every machine I saw would be loading 
boot sectors within a seconds of power-up.  Now my new machine is almost 
that fast, except it has this annoying 10-second delay while it looks to see 
if there's a DVD in the drive.  Come to think of it, I can probably fix that 
by telling it to look for the HD first...

Given that some laptop manufacturers are putting a dedicated button on the 
machine that says "just boot enough to play a DVD", this would seem to be a 
win. :-)

I do have to giggle at some of the reddit comments, tho.
http://www.reddit.com/r/linux/comments/742dw/making_linux_boot_in_less_than_five_seconds/
"I wonder if they could do the same magic with suspend and hibernate?"
"100% chance of waking up from suspend would be enough magic for me."

"Every CPU cycle is more coal burned at the plant."
"How much coal did it cost you to post that?"
"It's too shameful to answer."


-- 
   Darren New, San Diego CA, USA (PST)
   The NFL should go international. I'd pay to
   see the Detroit Lions vs the Roman Catholics.

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Darren New wrote:
> Given that some laptop manufacturers are putting a dedicated button on the
> machine that says "just boot enough to play a DVD", this would seem to be
> a win. :-)

My motherboard has a feature to play Audio CDs without booting an OS.

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On Thu, 11 Dec 2008 09:24:00 -0500, Tom Austin wrote:

> Jim Henderson wrote:
>> On Wed, 10 Dec 2008 16:27:30 -0500, Tom Austin wrote:
>> 
>>> actually now that I've had more time to think about it, I was actually
>>> using initramfs which has settings to build and pack with the kernel
>>> image.  Made it very simple indeed.
>> 
>> Oh, yeah, that definitely would make it simple.  :-)
>> 
>> Jim
> 
> What wasn't simple was figuring out that there was a problem with the
> the baud rate multiplier in my test setup.  I still don't understand the
> origins of it, but with a patch I got the gibberish turned into actual
> text.

That sounds similar to a problem that I've run into building Rockbox on 
my iPod with serial support (the interface on the bottom of the iPod is 
serial, from what I read, and any dock that adds functionality to the 
iPod uses that as its interface) - apparently the highly experimental 
serial driver doesn't always detect the baud rate correctly, and that can 
create interesting problems.  I imagine the control channel looks very 
much like gibberish. :-)

Jim

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On Wed, 10 Dec 2008 21:26:15 -0200, Nicolas Alvarez wrote:

> Jim Henderson wrote:
>> No Linux drivers for what high-end expensive graphics cards, exactly?
> 
> No accelerated Linux drivers for almost any graphics card.
> 
> ...I mean for DirectFB, not X :D

I don't know that that's a true statement, but I don't use DirectFB on my 
systems. :-)

Jim

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