[Buildroot] [PATCH v5] dpdk: new package

[Jan Viktorin]

Well, your config is for ARMv7 so no kmods are built because all current drivers require PCI which is hardly to see on this platform (I know just about Armada).

Ok. I don't know what would be the use case for dropping dependency on the kernel. Building just the rootfs without the kernel?

That means to check whether the kernel is enabled. And if it is then to enable building of the DPDK kernel modules. Right?

This can be done but I am afraid I have to disable certain modules by name from the current configuration. This is not very generic (consider adding a new out-of-tree kernel module or removing an obsolete one from the DPDK, custom DPDK tree with third party modules) but there are only few of them so it might be a working solution. I will check if there is a more generic way but I don't think so.
‎
Jan Viktorin
RehiveTech‎
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  Původní zpráva  
Od: Thomas Petazzoni
Odesláno: neděle, 17. dubna 2016 21:35
Komu: Jan Viktorin
Kopie: buildroot at buildroot.org
Předmět: Re: [Buildroot] [PATCH v5] dpdk: new package

Hello,

On Sun, 17 Apr 2016 17:56:07 +0200, Jan Viktorin wrote:

> what configuration do you use?

BR2_arm=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_TOOLCHAIN_EXTERNAL_CUSTOM=y
BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD=y
BR2_TOOLCHAIN_EXTERNAL_URL="http://autobuild.buildroot.org/toolchains/tarballs/br-arm-full-2016.02-3-g762b7c9.tar.bz2"
BR2_TOOLCHAIN_EXTERNAL_GCC_4_7=y
BR2_TOOLCHAIN_EXTERNAL_HEADERS_3_10=y
BR2_TOOLCHAIN_EXTERNAL_LOCALE=y
# BR2_TOOLCHAIN_EXTERNAL_HAS_THREADS_DEBUG is not set
BR2_TOOLCHAIN_EXTERNAL_INET_RPC=y
BR2_TOOLCHAIN_EXTERNAL_CXX=y
BR2_INIT_NONE=y
BR2_SYSTEM_BIN_SH_NONE=y
BR2_LINUX_KERNEL=y
BR2_LINUX_KERNEL_CUSTOM_VERSION=y
BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.5"
BR2_LINUX_KERNEL_DEFCONFIG="mvebu_v7"
# BR2_PACKAGE_BUSYBOX is not set
BR2_PACKAGE_DPDK=y
# BR2_TARGET_ROOTFS_TAR is not set

Before starting the build, I do "make linux-menuconfig", and enable
CONFIG_UIO in the kernel configuration.

> In general, I cannot say‎ we are always fine with the in-kernel
> modules. There are configurations of DPDK that build certain drivers.
> Of course, DPDK community would like to have no out-of-tree drivers.
> Some devices require a certain driver.
> 
> The x86 configuration builds drivers. The armv7 one doesn't (there
> are no useful drivers for this purpose).

Then IMO the dependency on the Linux kernel should be optional.

> A user may serve its own configuration of DPDK where a kernel driver
> is selected and thus, the user would expect it to be built and
> installed.

Right. But if the default configuration doesn't require the kernel to
be built, we probably shouldn't require it as well.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com