[Buildroot] [PATCH] xserver_xorg-server: use -O2 build optimization level

[Peter Seiderer]

On Fri, 6 May 2016 08:47:34 +0200, Peter Seiderer <ps.report at gmx.net> wrote:

> Hello Gustavo,
> 
> On Thu,  5 May 2016 21:08:27 -0300, Gustavo Zacarias <gustavo at zacarias.com.ar> wrote:
> 
> > The xorg server is somewhat sensitive to certain gcc versions combined
> > with -Os, particularly for ARM and MIPS, typically in the form of the
> > following symptom/error:
> > 
> > (EE) Segmentation fault at address 0x0
> > (EE)
> > Fatal server error:
> > (EE) Caught signal 11 (Segmentation fault). Server aborting
> > 
> > Force -O2 to work around this problem - for a target rootfs that uses
> > X11 the tradeoff is minimal since a sample/test image for qemu vexpress
> > with X11 + xinit + xterm + twm + xclock + gtk2 with demos is 60+ MB.
> > 
> > And it's less complicated than trying to find all of the bad
> > combinations.
> > 
> > Signed-off-by: Gustavo Zacarias <gustavo at zacarias.com.ar>
> > ---
> >  package/x11r7/xserver_xorg-server/xserver_xorg-server.mk | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/package/x11r7/xserver_xorg-server/xserver_xorg-server.mk b/package/x11r7/xserver_xorg-server/xserver_xorg-server.mk
> > index 617bcbc..9de6d91 100644
> > --- a/package/x11r7/xserver_xorg-server/xserver_xorg-server.mk
> > +++ b/package/x11r7/xserver_xorg-server/xserver_xorg-server.mk
> > @@ -62,7 +62,7 @@ XSERVER_XORG_SERVER_CONF_OPTS = \
> >  	--disable-xephyr \
> >  	--disable-dmx \
> >  	--with-builder-addr=buildroot at buildroot.org \
> > -	CFLAGS="$(TARGET_CFLAGS) -I$(STAGING_DIR)/usr/include/pixman-1" \
> > +	CFLAGS="$(TARGET_CFLAGS) -I$(STAGING_DIR)/usr/include/pixman-1 -O2" \
> >  	--with-fontrootdir=/usr/share/fonts/X11/ \
> >  	--$(if $(BR2_PACKAGE_XSERVER_XORG_SERVER_XVFB),en,dis)able-xvfb
> >  
> 
> Thanks for the patch, will surely improve the 'out of the box' usability of buildroot,
> but I would prefer a 'blacklist' of known failing combinations and simply disable
> xserver (with comment why) in this case(s), the only know to me is RPi1:
> 
>   BR2_ARCH="arm"
>   BR2_GCC_TARGET_CPU="arm1176jzf-s"
>   BR2_OPTIMIZE_S=y
> 

The original post [1] was about RPi2, so two known failing combinations ;-)

Curious if its the same failure location as for RPi1 (see [2]), anyone with
RPi2 hardware who could try to run with debug info enabled (and/or the reduced
test case from the bug report)?

Regards,
Peter

[1] http://lists.busybox.net/pipermail/buildroot/2016-May/160491.html
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63346


> The perfect solution would be a fix for gcc (and/or xserver)...
> 
> Regards,
> Peter
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