radu
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Re: Preinstalled kernel modules

Tue Nov 22, 2011 10:42 pm

With a shipment estimate for December/January, did you guys decide which kernel modules/drivers are you going to ship with your 'official' distribution?
Can we request what devices we would like to be supported by default? Or are we supposed to compile our own kernels with whatever we need?

dom
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Re: Preinstalled kernel modules

Tue Nov 22, 2011 10:55 pm

Yes, this is up for negiotiation.

If there are features or drivers you think are important to enable, then please post.
These should be supported in the .config file of 2.6.35 kernel.

Obviously you can build your own kernel (or ask nicely) if you have unusual requirements, but it would be good to have the most common options covered for a default kernel.

radu
Posts: 110
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Re: Preinstalled kernel modules

Tue Nov 22, 2011 11:18 pm

Excellent, thanks!
Here is what I have in mind:
1. USB sound (especially for those wireless headsets)
2. Some Wifi stuff, perhaps a few chipsets, based on Amazon/Newegg cheapest adapters.
3. Webcams (this is more or less generic I think).
3. Some BT support, again, probably the most popular chipsets.
4. Some 3G/4G modems support would also be very nice for a lot of applications.
5. Maybe some USB to COM adapters as well, this would be good for hobbyists that need COM for legacy stuff.

I think this should cover most needs.

Chris Tyler
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Re: Preinstalled kernel modules

Wed Nov 23, 2011 2:05 am

The only easy expansion option is via USB, so what about a kernel with built-in drivers for all of the on-board devices, loadable modules for all available USB devices (and related pieces such as sound and bluetooth stack), and no other device drivers?

In terms of non-device driver modules, it would be nice to have a fairly comprehensive set of network and storage modules (nbd, aoe, ipv6, lvm).

Layout-wise:
- The kernel is on partition 1, and the modules have to match the kernel, so it would be reasonable to put the modules on partition 1 ( in /modules/$(uname -r) ) so they can be easily upgraded together.
- Partition 1 should be mounted at /boot (e.g., for changing cmdline.txt)
- In the root filesystem, /lib/modules can therefore be a symlink to /boot/modules

obarthelemy
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Re: Preinstalled kernel modules

Wed Nov 23, 2011 2:20 am

I Spend half my life in Androids and Linuxes looking for cifs.ko. I'm sure UKscone would appreciate not having to rebuild me a kernel for that, for once ^^

kme
Posts: 448
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Re: Preinstalled kernel modules

Wed Nov 23, 2011 2:31 am

Quote from Chris Tyler on November 23, 2011, 02:05
The only easy expansion option is via USB, so what about a kernel with built-in drivers for all of the on-board devices, loadable modules for all available USB devices (and related pieces such as sound and bluetooth stack), and no other device drivers?

In terms of non-device driver modules, it would be nice to have a fairly comprehensive set of network and storage modules (nbd, aoe, ipv6, lvm).

Layout-wise:
- The kernel is on partition 1, and the modules have to match the kernel, so it would be reasonable to put the modules on partition 1 ( in /modules/$(uname -r) ) so they can be easily upgraded together.
- Partition 1 should be mounted at /boot (e.g., for changing cmdline.txt)
- In the root filesystem, /lib/modules can therefore be a symlink to /boot/modules
This sounds sensible (well maybe lvm is a bit over the hill for something on a USB2 bus). A vfat partition 1 on 50 MB should be plenty then?

seafrog
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Re: Preinstalled kernel modules

Wed Nov 23, 2011 3:15 am

For the drivers, I assume SPI is installed anyway, but I2C and GPIO drivers would be much appricated.

I am not certain what the SOC is capable of but (software) PWM would be a perfect.

Besides that thanks and congratulation for your work.

hippy
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Location: UK

Re: Preinstalled kernel modules

Wed Nov 23, 2011 2:40 pm

Quote from Chris Tyler on November 23, 2011, 02:05
The only easy expansion option is via USB, so what about a kernel with built-in drivers for all of the on-board devices, loadable modules for all available USB devices (and related pieces such as sound and bluetooth stack), and no other device drivers?


That would make sense to me; keep the kernel as small as possible but able to use all the R-Pi board hardware 'as is', all other modules / drivers / whatever Linux calls them to be loaded as required. It's going to be far easier for users to alter the init scripts to include those wanted than to recompile a kernel to take them out when not wanted.

It does of course depend on how big the overhead is; a few bytes may be worthwhile but I'd prefer to have more memory available than have it wasted by a kernel which includes things I won't be using.

jamesh
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Re: Preinstalled kernel modules

Wed Nov 23, 2011 3:03 pm

I'd want USB Serial by default - think quite a few people might want that, and that would also help with USB GPS, ODBCII modules as they tend to use that sort of thing. Still not got my GPS device working - must find some time!

Most of these drivers are pretty small, so I don't think kernel size is particularly affected by including a whole bunch of them.
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hippy
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Re: Preinstalled kernel modules

Wed Nov 23, 2011 6:24 pm

Quote from jamesh on November 23, 2011, 15:03
I'd want USB Serial by default - think quite a few people might want that


Agreed; it's the easiest means to interface to microcontrollers. Prolific PL2303 and FTDI drivers would probably cover most people.

Quote from jamesh on November 23, 2011, 15:03
Most of these drivers are pretty small, so I don't think kernel size is particularly affected by including a whole bunch of them.


I'm happy with as much as people think is reasonable. It was the thought of having MB's of Bluetooth or WiFi driver / protocol stack that worried me. If small, no problem.

AlanCox
Posts: 31
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Re: Preinstalled kernel modules

Tue Nov 29, 2011 10:32 pm

Given almost all the stacks and other bits are modular you can build an 'everything USB' kernel and then just put some of the drivers (the ones you want) plus their dependancies on the SD card.

It's something the bigger distros like Fedora simply assume isn't worth bothering with but in a small embedded setup its perfectly possible to have a pile of kernel-foo packages spat out for the different modules.

For serial btw you want both the USB serial drivers and also ACM (the modem emulation class). Some devices use each.

I'd also suggest including the USB video interface drivers, particularly given the A model, that way you can plug in a USB displaylink monitor (or touchscreen monitor to be flash) and use it for debug.

tntexplosivesltd
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Re: Preinstalled kernel modules

Tue Nov 29, 2011 10:41 pm

The R-Pi has 2 alternate forms of video output, why use a third?

sylvan
Posts: 118
Joined: Sun Nov 27, 2011 8:39 pm

Re: Preinstalled kernel modules

Wed Nov 30, 2011 12:42 am

Quote from hippy on November 23, 2011, 14:40
Quote from Chris Tyler on November 23, 2011, 02:05
The only easy expansion option is via USB, so what about a kernel with built-in drivers for all of the on-board devices, loadable modules for all available USB devices (and related pieces such as sound and bluetooth stack), and no other device drivers?


That would make sense to me; keep the kernel as small as possible but able to use all the R-Pi board hardware 'as is', all other modules / drivers / whatever Linux calls them to be loaded as required. It's going to be far easier for users to alter the init scripts to include those wanted than to recompile a kernel to take them out when not wanted.

It does of course depend on how big the overhead is; a few bytes may be worthwhile but I'd prefer to have more memory available than have it wasted by a kernel which includes things I won't be using.

Exactly right.

And along those lines, do not build ANY optional drivers into the kernel, including for the on-board devices!

Included drivers use memory, and they also make it boot slower since every included driver has to be loaded before the kernel is started.

Every desirable driver should be a module. In addition to decreased memory usage and faster boot, it is a lot easier to replace or patch a module if a minor driver tweak is needed.

PiOfCube
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Re: Preinstalled kernel modules

Wed Nov 30, 2011 1:30 am

IrDA support would be great (IrCOMM and IrDA-USB would be a real bonus also).

I'm not sure what the 2.6.35 kernel has regarding IrDA as it seems a few of the projects aren't updated anymore.
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asb
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Re: Preinstalled kernel modules

Wed Nov 30, 2011 7:54 am

I believe the plan is to build modules for pretty much everything. If there's an oversight, it can easily enough be corrected (and it's not hard to build the module yourself).

hippy
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Re: Preinstalled kernel modules

Wed Nov 30, 2011 12:28 pm

Quote from asb on November 30, 2011, 07:54
(and it's not hard to build the module yourself).

That sometimes isn't the reality for those who don't have prior experience. As long as there's a detailed enough guide for the distro being used showing where the tools required can be found, how they are installed, configured and used ( and likewise for any prerequisites ) then it shouldn't be a problem and there should be guiding hands from the R-Pi community.

Hopefully there will be some repository of modules for R-Pi users so any effort to create new modules won't have to be repeated and perhaps there may be experienced members of the community willing to undertake compilation and distribution to the repository on behalf of others who are having difficulties.

There's certainly merit in having people learn to build all that they need but there's also an advantage in making it as easy as possible for newcomers and the inexperienced to use.

eggn1n3
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Re: Preinstalled kernel modules

Wed Nov 30, 2011 1:11 pm

Has it already been confirmed which kernel will be used at the launch? Is that 2.6.35?

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