maemo.org - Talk - Compiling custom kernels for P1.1 (with fiasco-gen)

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- - Compiling custom kernels for P1.1 (with fiasco-gen) (https://talk.maemo.org/showthread.php?t=43420)

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

Hi!

Can we have the gadgetfs (!= g_file_storage) driver in the next kernel or compiled as a standlone module for power46? This would, among others, allow to simulate a USB keyboard with the N900.

Thanks!

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

Quote:

Originally Posted by craftyguy (Post 923572)

I don't get it, why would you use a ramdisk for swap? The whole reason the kernel even uses swap is to take inactive pages out of memory so there is room for active pages. By creating a ramdisk, you reduce the amount of RAM you can use for these active pages. Maybe to reduce wear on the flash device? I think this would ultimately reduce performance since your usable RAM size will be significantly reduced?

The point is that the swap is compressed. Lets say you allow zram0 to be a device that is 128MB (half your ram) and that zram achievs a 50% compression. Without going to physical swap (flash) you now have effectively 128+(128*2) = 384MB ram to work with - yes stuff is going to have to be compressed in and out mean CPU load, but the compression is lite and fast, and if your physical swap is slow, thats still preferable.

It's been a huge win for me on other constrained devices even with faster storage.

For example on a VPS I use:

DiskSize: 524288 kB
OrigDataSize: 104852 kB
ComprDataSize: 36712 kB
MemUsedTotal: 37848 kB

So I've given up 37MB to store 105MB - thats a gain (on a fairly small vps) of 68MB - if the compression stays the same and I use all the allocation - thats approx gain of 300MB on a 1GB system by using 200MB of RAM for the compression. I could be more aggressive too...

I use it on my laptop and desktop as well to great effect.

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

Quote:

Originally Posted by phedders (Post 933868)

The point is that the swap is compressed.
[...]

It's been a huge win for me on other constrained devices even with faster storage.

I just want to echo the great (qualitative) experience I have had with ramzswap on constrained devices. Given it helps with crappy programs / libraries's memory usage, and the lack of disincentives to fix those, it's almost sure to be beneficial for a long time in the future.

Since one is (to oversimplify a tiny bit) trading CPU for RAM, with ~1GHz devices these days only having 256MB of RAM that's usually a win. Even on the OLPC XO-1 with 400MHz CPU and 256MB of RAM it was a win (since the greatest performance optimization is to go from a non-working state to a working state, and yum/rpm are quite memory-hungry at times).

Martin

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

I'd like to create bridges with the current stable power kernel, however it seems that the bridge module is missing. Is there some way for me to generate this module myself or can anyone supply me with it? Until then, brctl will continue to throw "add bridge failed: Package not installed" my way...

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

Hi there!

I have installed the sdk-fiasco-gen with dpkg but when I do the "fakeroot apt-get build-dep kernel-power" I got:

Build-Depends dependency for kernel-power cannot be satisfied because the package sdk-fiasco-gen cannot be found

how is it possible???

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

I tried also:

cp debian/rx51power_defconfig arch/arm/configs/

make EXTRAVERSION=power46 rx51power_defconfig

make EXTRAVERSION=power46 bzImage

but I got: In file included from arch/arm/mach-omap2/pm.c:37:
arch/arm/plat-omap/include/mach/pm.h:111:2: error: #error "Power management for this processor not implemented yet"

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

Quote:

Originally Posted by Bernard (Post 913304)

How do I compile a kernel-power kernel myself?

I followed guides on compiling kernel in scratchbox using information:
http://wiki.maemo.org/Documentation/...o_Kernel_Guide
and
http://www.natisbad.org/N900/n900-custom-kernel.html

the default nokia kernel seems to compile but the power kernel doesn't. As suggested here, I tried the extra step in copying the default config:
http://psfreedom.com/wiki/Nokia_N900...9_maemo_kernel

Code:

cp debian/rx51power_defconfig arch/arm/configs/

But when I do "make EXTRAVERSION=.10power46" I stil get an error:

Code:

In file included from arch/arm/mach-omap2/pm.c:37:

arch/arm/plat-omap/include/mach/pm.h:111:2: error: #error "Power management for this processor not implemented yet"

make[1]: *** [arch/arm/mach-omap2/pm.o] Error 1

make: *** [arch/arm/mach-omap2] Error 2

If I only compile modules, that seems to work OK, but compiling the entire kernel doesn't work.

Can anybody help me?

Hi Bernard,

same problem.

I modified the arch/arm/plat-omap/include/mach/pm.h file commenting the error code message.

It compiles for a while but after I get this other error :(

LD .tmp_vmlinux1
/scratchbox/compilers/cs2007q3-glibc2.5-arm7/bin/sbox-arm-none-linux-gnueabi-ld: no machine record defined
/scratchbox/compilers/cs2007q3-glibc2.5-arm7/bin/sbox-arm-none-linux-gnueabi-ld: no machine record defined

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

I'm also failing when I try to rebuild the "stock" power46 kernel with the same "Power management for this processor not implemented yet" error.

I'm trying to include the android-specific patches into the kernel and while it seems to be working with the original kernel from Nokia I would definitely prefer to do the work on the power kernel series...

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

Has anyone evaluate power consumption of kernel?

I mean, I would like to know whether the community kernel has a bigger consumption than former Nokia one or similar?

Re: Compiling custom kernels for P1.1 (with fiasco-gen)

Would it be possible for a future build of the power kernel to include the snd_usb_audio module/drivers?

With USB host mode support I'd like to have a go at getting an external mic working with the n900, the mic powers and appears to get sufficient power, but no drivers are present.