[sane-devel] inb outb missing on mips

[Luiz Angelo Daros de Luca]

I added some autoconf magic in order to detect missing inb,outb functions.
It might not be the best solution
as I'm no autoconf expert but it solves my problems.

https://raw.githubusercontent.com/luizluca/openwrt-packages/e11fbf71f7f437c64d18929e7895dbaafa8c3293/utils/sane-backends/patches/020-inb_outb.patch

Regards,

Em qui, 10 de set de 2015 às 01:14, Luiz Angelo Daros de Luca <
luizluca at gmail.com> escreveu:

> Hello,
>
> I checked with other libc and got some more info about the problem.
>
> Normally, sane-backends deal with ioperm/inb/outb like this:
> a) sane-backends tries to use sys/io.h in order to provide inb/outb. If
> missing, it implements them locally but only for i386 (old glibc?)
> b) if ioperm is missing for any arch but i386. IO_SUPPORT_MISSING is
> defined
> c) if either ioperm is missing or IO_SUPPORT_MISSING is defined, inb/outb
> will not be used.
> c.1) the exception is backend/qcam.c, which tries to use inb/outb anyway
> but it will not be compiled if ioperm is missing.
>
> Now how libc implementations deal with iopem/inb/oub:
>
> When uclibc is used:
> * it provide sys/io.h for only i386/x32/x86_64 archs and it includes
>  inb/outb
> * it does not provide sys/io.h for non i386 arch
> When musl is used:
> * it provides sys/io.h for any arch that has ioperm syscall (which
> includes mips, i386/x32/x86_64, powerpc, microblaze)
> * it does not provide inb/outb for any arch expect i386/x32/x86_64 (using
> bits/io.h included in sys/io.h)
>
> What happens on sane-backend:
> 1) for i386/x32/x86_64 arch, any libc provides sys/io.h with ioperm and
> inb/oub. Sane-backends compiles.
> 2) for any arch that does not implement ioperm syscall, ioperm is
> missing. Sane-backends compiles.
> 3) for other non-i386/x32/x86_64-arch that provides ioperm syscall:
> 3.1) uclibc does not provide sys.io.h. Sane-backends compiles, except for
> qcam.
> 3.2) musl provide sys.io.h but inb/outb is missing. Sane-backends fails
> with multiple undefined symbols (inb/outb).
>
> Some files affected are:
> sanei/sanei_pio.c
> sanei/sanei_ab306.c
> sanei/sanei_pa4s2.c
> sanei/sanei_pp.c
> backend/umax_pp_low.c
> backend/qcam.c
>
> What is the best solution here? Should all checks for ioperm be replaced
> by (or added with) checks for inb/outb (including disabling qcam in
> configure)?
> It'll not break cases 1), 2) and it will fix 3.1 and 3.2.
>
> Regards,
>
>
>
>
> Em qua, 9 de set de 2015 às 19:04, Luiz Angelo Daros de Luca <
> luizluca at gmail.com> escreveu:
>
>> Hello,
>>
>> I'm trying to get rid of this patch:
>>
>> http://git.openwrt.org/?p=packages.git;a=blob_plain;f=utils/sane-backends/patches/020-non-i386-qcam.patch;hb=HEAD
>>
>> That helps sane-backend cross-compile for MIPS processor. But this seems
>> to be a hacky solution.
>>
>> The problem seems that configure check for ioperm passes for MIPS with
>> libc-musl (I didn't test with other libc), while inb and outb are still
>> missing for this arch. As sane-backend uses HAVE_IOPERM in order to use or
>> not in/outb, it compiles requiring inb/outb. This results in a linker error.
>>
>> Who is not playing nice here? musl providing ioperm where it shouldn't?
>> configure failing to check correcly for ioperm? sane not checking for inb?
>>
>> Regards,
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.alioth.debian.org/pipermail/sane-devel/attachments/20150910/5f3e51c8/attachment-0001.html>