From 3dcceb5743dacdd413e0981b2f20747b30ac9353 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 8 Jul 2019 15:52:08 +0200 Subject: [PATCH 2846/2940] drm/amd/display: avoid 64-bit division On 32-bit architectures, dividing a 64-bit integer in the kernel leads to a link error: ERROR: "__udivdi3" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined! ERROR: "__divdi3" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined! Change the two recently introduced instances to a multiply+shift operation that is also much cheaper on 32-bit architectures. We can do that here, since both of them are really 32-bit numbers that change a few percent. Fixes: bedbbe6af4be ("drm/amd/display: Move link functions from dc to dc_link") Fixes: f18bc4e53ad6 ("drm/amd/display: update calculated bounding box logic for NV") Acked-by: Slava Abramov Tested-by: Slava Abramov Signed-off-by: Arnd Bergmann Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 4 ++-- drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c index e94d65ad0d90..dbc925273512 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -3070,8 +3070,8 @@ uint32_t dc_link_bandwidth_kbps( * but the difference is minimal and is in a safe direction, * which all works well around potential ambiguity of DP 1.4a spec. */ - long long fec_link_bw_kbps = link_bw_kbps * 970LL; - link_bw_kbps = (uint32_t)(fec_link_bw_kbps / 1000LL); + link_bw_kbps = mul_u64_u32_shr(BIT_ULL(32) * 970LL / 1000, + link_bw_kbps, 32); } #endif diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c index 385a36f51f43..14920c180836 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c @@ -2655,7 +2655,7 @@ static void update_bounding_box(struct dc *dc, struct _vcs_dpi_soc_bounding_box_ calculated_states[i].dram_speed_mts = uclk_states[i] * 16 / 1000; // FCLK:UCLK ratio is 1.08 - min_fclk_required_by_uclk = ((unsigned long long)uclk_states[i]) * 1080 / 1000000; + min_fclk_required_by_uclk = mul_u64_u32_shr(BIT_ULL(32) * 1080 / 1000000, uclk_states[i], 32); calculated_states[i].fabricclk_mhz = (min_fclk_required_by_uclk < min_dcfclk) ? min_dcfclk : min_fclk_required_by_uclk; -- 2.17.1