Re: Floating point exception in Xorg

[Neil MacMunn <neil@gumstix.com>]

On 11-03-04 12:26 PM, Phil Blundell wrote:
> On Fri, 2011-03-04 at 11:57 -0800, Neil MacMunn wrote:
>>> #1  0x40661fbc in __div0 ()
>>>      at /home/neil/overo-oe/tmp-unstable/work/armv7a-angstrom-linux-gnueabi/gcc-cross-4.3.3-r23.2/gcc-4.3.3/libgcc/../gcc/config/arm/lib1funcs.asm:1079
>>> #2  0x40661f90 in __udivsi3 ()
>>>      at /home/neil/overo-oe/tmp-unstable/work/armv7a-angstrom-linux-gnueabi/gcc-cross-4.3.3-r23.2/gcc-4.3.3/libgcc/../gcc/config/arm/lib1funcs.asm:834
>>> #3  0x4065edc4 in OMAPFBOutputGetModes (output=<value optimized out>)
>>>      at omapfb-output.c:128
>>> #4  0x000f8c60 in xf86ProbeOutputModes (scrn=0x90a990, maxX=2048, maxY=2048)
>>>      at xf86Crtc.c:1575
>
> That's a division by zero in what looks like the mode selection code.
> At a guess, some parameter which the server is relying on to calculate
> the video timings is not being set correctly by the kernel.  You'd need
> to inspect the source for OMAPFBOutputGetModes() to figure out what's
> up, though.
>
> p.
>


Right. This line is the problem.

>  mode->Clock = PICOS2KHZ(ofb->state_info.pixclock);

because

>  #define PICOS2KHZ(a) (1000000000UL/(a))

I didn't have any luck figuring out where pixclock was supposed to be 
set so I just reverted xf86-video-omapfb_git.bb and my LCDs work again.

> git checkout 3b039e5c54265c5e1e254736687ad1cefed8f534 -- xf86-video-omapfb_git.bb

Thanks for the help.

--
Neil