[PATCH] drm/amd/display: fix 64-bit integer division

[Stempen, Vladimir]

[AMD Official Use Only - Internal Distribution Only]

Hi Arnd,
I have all the patches ready and I have tested them with the feature/platform I'm working on and Bindu helped to test the 32bit build.
I'm in process of submitting the latest change.
Thanks,
Vladimir.

On 2021-02-25, 4:36 PM, "Arnd Bergmann" <arnd at kernel.org> wrote:

    On Thu, Feb 25, 2021 at 3:33 PM Arnd Bergmann <arnd at kernel.org> wrote:
    >
    > From: Arnd Bergmann <arnd at arndb.de>
    >
    > The new display synchronization code caused a regression
    > on all 32-bit architectures:
    >
    > ld.lld: error: undefined symbol: __aeabi_uldivmod
    > >>> referenced by dce_clock_source.c
    > >>>               gpu/drm/amd/display/dc/dce/dce_clock_source.o:(get_pixel_clk_frequency_100hz) in archive drivers/built-in.a
    >
    > ld.lld: error: undefined symbol: __aeabi_ldivmod
    > >>> referenced by dc_resource.c
    > >>>               gpu/drm/amd/display/dc/core/dc_resource.o:(resource_are_vblanks_synchronizable) in archive drivers/built-in.a
    > >>> referenced by dc_resource.c
    > >>>               gpu/drm/amd/display/dc/core/dc_resource.o:(resource_are_vblanks_synchronizable) in archive drivers/built-in.a
    > >>> referenced by dc_resource.c
    > >>>               gpu/drm/amd/display/dc/core/dc_resource.o:(resource_are_vblanks_synchronizable) in archive drivers/built-in.a
    >
    > This is not a fast path, so the use of an explicit div_u64/div_s64
    > seems appropriate.

    I found two more instances:

    >>> referenced by dcn20_optc.c
    >>>               gpu/drm/amd/display/dc/dcn20/dcn20_optc.o:(optc2_align_vblanks) in archive drivers/built-in.a

    >>> referenced by dcn10_hw_sequencer.c
    >>>               gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.o:(reduceSizeAndFraction) in archive drivers/built-in.a

    I have patches for both, but will let the randconfig build box keep working
    on it over night to see if there are any others. Let me know if you want a
    combined patch or one per file once there are no more regressions.

            Arnd