[libcamera-devel] [PATCH] src/ipa/raspberrypi/raspberrypi.cpp: drop constexpr for division

[Fabrice Fontaine]

Hi Laurent,

Le ven. 15 oct. 2021 à 19:15, Laurent Pinchart
<laurent.pinchart at ideasonboard.com> a écrit :
>
> Hi Fabrice,
>
> Thank you for the patch.
>
> On Fri, Oct 15, 2021 at 07:02:32PM +0200, Fabrice Fontaine wrote:
> > For an unknown reason, build fails with some embedded toolchains since
> > commit 92b8ccc42a0f3ad323c79bde3c132d6956011239 on:
> >
> > In file included from ../include/libcamera/base/log.h:10,
> >                  from ../src/ipa/raspberrypi/raspberrypi.cpp:18:
> > ../src/ipa/raspberrypi/raspberrypi.cpp:64:53:   in 'constexpr' expansion of 'std::chrono::operator/<long double, std::ratio<1>, double>(std::literals::chrono_literals::operator""s(1.0e+0l), 3.0e+1)'
> > /home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/powerpc64-buildroot-linux-gnu/include/c++/9.3.0/chrono:502:32: error: '(1.0e+0l / 3.0e+1)' is not a constant expression
> >   502 |  return __cd(__cd(__d).count() / __s);
> > ../src/ipa/raspberrypi/raspberrypi.cpp:73:56:   in 'constexpr' expansion of 'std::chrono::operator/<long double, std::ratio<1>, double>(std::literals::chrono_literals::operator""s(1.0e+0l), 6.0e+1)'
> > /home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/powerpc64-buildroot-linux-gnu/include/c++/9.3.0/chrono:502:32: error: '(1.0e+0l / 6.0e+1)' is not a constant expression
>
> This seems like it could be a toolchain bug. Does it work with newer gcc
> versions on powerpc64 ?
It builds fine with other toolchains.
>
> Given that RPi is an ARM64 platform, I'd rather disable compilation of
> RPi support on powerpc64 instead of possibly harming the main user.
OK, thanks for your feedback, I'll update buildroot.
>
> > So drop constexpr for both divisions to fix this build failure.
> >
> > Fixes:
> >  - http://autobuild.buildroot.org/results/49caebe7ef7e3d63de49e78d5d6839dd0aedf10c
> >
> > Signed-off-by: Fabrice Fontaine <fontaine.fabrice at gmail.com>
> > ---
> >  src/ipa/raspberrypi/raspberrypi.cpp | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
> > index fed82e22..8ffb7092 100644
> > --- a/src/ipa/raspberrypi/raspberrypi.cpp
> > +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> > @@ -61,7 +61,7 @@ using utils::Duration;
> >  /* Configure the sensor with these values initially. */
> >  constexpr double defaultAnalogueGain = 1.0;
> >  constexpr Duration defaultExposureTime = 20.0ms;
> > -constexpr Duration defaultMinFrameDuration = 1.0s / 30.0;
> > +Duration defaultMinFrameDuration = 1.0s / 30.0;
> >  constexpr Duration defaultMaxFrameDuration = 250.0s;
> >
> >  /*
> > @@ -70,7 +70,7 @@ constexpr Duration defaultMaxFrameDuration = 250.0s;
> >   * we rate-limit the controller Prepare() and Process() calls to lower than or
> >   * equal to this rate.
> >   */
> > -constexpr Duration controllerMinFrameDuration = 1.0s / 60.0;
> > +Duration controllerMinFrameDuration = 1.0s / 60.0;
> >
> >  LOG_DEFINE_CATEGORY(IPARPI)
> >
>
> --
> Regards,
>
> Laurent Pinchart
Best Regards,

Fabrice