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

[Laurent Pinchart]

Hi Fabrice,

On Fri, Oct 15, 2021 at 08:28:22PM +0200, Fabrice Fontaine wrote:
> Le ven. 15 oct. 2021 à 19:15, Laurent Pinchart a écrit :
> > 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.

Does that include newer powerpc64 toolchains ? I'd like to know if we
should report a bug to gcc of if it's fixed already.

> > 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.

Thank you.

> > > 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