Re: (Hardware?) problem with denormal values on mipsel
On Wed, 27 May 2015, James Cowgill wrote:
> Thanks! The kernel was the important part which was different to my
> setup.
>
> There's probably still a hardware bug in here somewhere, but before 3.16
> the kernel was fixing it with the math emulator.
>
> From what I can see:
> Commit 08a07904e182 in 3.16 ('MIPS: math-emu: Remove most ifdefery.')
> incorrectly disabled emulation of the sqrt.s instruction on processors
> only supporting the mips2/mips3 ISA.
>
> Commit 7352c8b13dd9 in 3.18 ('MIPS: Loongson: Set Loongson-3's ISA level
> to MIPS64R1') worked around this in the Loongson 3s because their ISA
> level was bumped to mips64r1.
>
> Commit 2d83fea786d7 in 4.1-rc1 ('MIPS: Correct FP ISA requirements')
> fixed the underlying sqrt.s emulation bug.
>
> It would be good if the 4.1-rc1 patch or at least the 'case fsqrt_op'
> part (which is the fix for this bug) can be applied to a jessie stable
> kernel and then installed on the buildds. This should fix the original
> problem of eso-midas failing to build on mipsel.
What's the actual problem here, how can I help?
Maciej
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