Re: [gentoo-user] Anybody got a Gentoo system working under uclibc?

[Corbin <corbinbird@charter.net>]

On 04/27/2016 04:31 PM, waltdnes@waltdnes.org wrote:
> On Wed, Apr 27, 2016 at 12:25:41PM -0500, Corbin wrote
>>
>> On 04/27/2016 09:12 AM, waltdnes@waltdnes.org wrote:
>>>     I'm testing uclibc in a 32-bit QEMU Gentoo VM.  I want to eventually
>>> install on my ancient 32-bit-only netbook.  I'm running into problems.
>>> See https://forums.gentoo.org/viewtopic-p-7912494.html
>>>
>>>     To summarize...
>>>     * static IP works for eth0, but dhcpcd fails, which is bad news for a
>>>       laptop or netbook
>>>     * when building x-rg-server, the builds for xf86-input-keyboard and
>>>       xf86-video-intel fail to compile
>>>     * www-client/w3m fails to build, so I can't even get decent textmode
>>>       web browsing
>>>
>>
>> You already found my test load :)
>> Glad it helped someone.
>>
>> Did you have/add "evdev" in "make.conf" for INPUT_DEVICES?
>> "evdev" is built-into-the-kernel or a kernel module. The newer input
>> function, augmenting/replacing the AT keyboard and /dev/psaux.
>> ( Seems "evdev" is almost replacing the functions of "xf86-input"
>> libraries for Xorg.)
>
>    No.  Do I have to set something in the kernel?  Will the keyboard work
> with evdev and without xf86-input-keyboard?  My netbook uses framebuffer
> video driver, so I might try using that in the uclibc VM.
>
>> What CPU flags did you set/unset for the build?
>>
>> My reason for asking ... a lot of software has an unmarked dependency on
>> "sse/sse2". If the info on the Atom CPU I found was correct ... it
>> doesn't have sse/sse2 instruction sets.
>
>    My Atom netbook has them, according to /proc/cpuinfo
>
> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
> mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx
> constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl
> vmx est tm2 ssse3 xtpr pdcm movbe lahf_lm dtherm tpr_shadow vnmi
> flexpriority
>
>    Note also the "movbe" flag.  *I CANNOT TEST RUN MY NETBOOK-OPTIMIZED
> CODE I BUILD IN THE QEMU VM*.  QEMU claims to emulate "Atom" CPUs.
> There are over 100 different atoms in the periodic table known to
> physicists, and Intel is just as bad, with all their "Atom" variants.
> QEMU's "Atom" emulation does not support the "movbe" flag.  So I simply
> run with the host CPU in a 32-bit VM, and set "-march=native".  When
> building for the netbook, I build with "-march=bonnell".  Important
> distinction...
>
> different "-march" values != crossdev
>
>    As long as the "CHOST" variable is identical, you can build for
> different "-march" variants, even those that won't run in the build
> environment.
>
>> Useful Info : https://wiki.gentoo.org/wiki/Safe_CFLAGS
>
> See also http://gentoo-en.vfose.ru/wiki/Safe_Cflags#-march.3Dnative
>
> gcc -march=native -E -v - </dev/null 2>&1 | grep cc1
>
>    Ignore all the fancy flags.  Both of those pages come up with output
> that shows "-march=bonnell" on my Atom
> https://en.wikipedia.org/wiki/Bonnell_%28microarchitecture%29
>
>    I have a standard glibc 32-bit VM which I use for Gentoo distcc for
> the Atom, as well as manually building Pale Moon web browser.  I use the
> following settings for both...
>
> CFLAGS="-O2 -march=bonnell -mfpmath=sse -pipe -fomit-frame-pointer \
> -fno-unwind-tables -fno-asynchronous-unwind-tables"
>
> CCFLAGS="${CFLAGS}"
>
>    "-march=bonnell" implies all the other flags, so no need to enter them
> into the CFLAGS variable.
>
>    Thanks for that initial post.  I had almost given up on even a minimal
> install, before I found it.
>

Your Welcome.

Link for "evdev" : https://en.wikipedia.org/wiki/Evdev

The default kernel config has "evdev" built into the kernel.

On my desktop, Nvidia drivers do look for and use "evdev" without 
Wayland support in Xorg. ( XFCE )

This might be pedantic ...
... add "sse sse2 sse3 ssse3 mmx acpi -mmxext" to your USE flags in 
"make.conf" ( if not already present. ) Some packages look for those 
flags in strange ways.

Using a one-problem-at-a-time approach ...

< Proposed Test / Xorg Fix >
... adding "libinput" to the USE flags in your "make.conf".
... setting INPUT_DEVICES="evdev" in "make.conf".

Desktops that should work with "libinput/evdev" ONLY are QT4, QT5, XFCE.
XFCE provides its own keyboard library and config applets/plugins. Don't 
know about QT4 / QT5.

If you have not already done this ... might want to set 
VIDEO_CARDS="fbdev vesa" or just "fbdev" to save compile time.

This is getting very interesting.
Please let us know how this works out :)