[PATCH] drm/amd/display: Fix 64-bit division error on 32-bit platforms in mod_freesync_build_vrr_params

From: Nathan Chancellor
Date: Mon Mar 30 2020 - 18:16:37 EST


When building arm32 allyesconfig,

ld.lld: error: undefined symbol: __aeabi_uldivmod
>>> referenced by freesync.c
>>> gpu/drm/amd/display/modules/freesync/freesync.o:(mod_freesync_build_vrr_params) in archive drivers/built-in.a
>>> did you mean: __aeabi_uidivmod
>>> defined in: arch/arm/lib/lib.a(lib1funcs.o)

Use div_u64 in the two locations that do 64-bit divisior, which both
have a u64 dividend and u32 divisor.

Fixes: 349a370781de ("drm/amd/display: LFC not working on 2.0x range monitors")
Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
---
drivers/gpu/drm/amd/display/modules/freesync/freesync.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
index 8911f01671aa..c33454a9e0b4 100644
--- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
+++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
@@ -761,10 +761,10 @@ void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,

// If a monitor reports exactly max refresh of 2x of min, enforce it on nominal
rounded_nominal_in_uhz =
- ((nominal_field_rate_in_uhz + 50000) / 100000) * 100000;
+ div_u64(nominal_field_rate_in_uhz + 50000, 100000) * 100000;
if (in_config->max_refresh_in_uhz == (2 * in_config->min_refresh_in_uhz) &&
in_config->max_refresh_in_uhz == rounded_nominal_in_uhz)
- min_refresh_in_uhz = nominal_field_rate_in_uhz / 2;
+ min_refresh_in_uhz = div_u64(nominal_field_rate_in_uhz, 2);

if (!vrr_settings_require_update(core_freesync,
in_config, (unsigned int)min_refresh_in_uhz, (unsigned int)max_refresh_in_uhz,
--
2.26.0