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| author | Arnd Bergmann | 2019-07-08 15:52:08 +0200 |
|---|---|---|
| committer | Alex Deucher | 2019-07-08 21:27:23 +0200 |
| commit | 5f65ae344f1493c9c6f0a1748da4ce3af71ab541 (patch) | |
| tree | 0bc01f7ec039cd2babe6b09d144b879deb3f1939 /drivers/gpu/drm/amd/display/dc/core/dc_link.c | |
| parent | drm/amdgpu/psp11: simplify the ucode register logic (diff) | |
| download | kernel-qcow2-linux-5f65ae344f1493c9c6f0a1748da4ce3af71ab541.tar.gz kernel-qcow2-linux-5f65ae344f1493c9c6f0a1748da4ce3af71ab541.tar.xz kernel-qcow2-linux-5f65ae344f1493c9c6f0a1748da4ce3af71ab541.zip | |
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 <slava.abramov@amd.com>
Tested-by: Slava Abramov <slava.abramov@amd.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/amd/display/dc/core/dc_link.c')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/core/dc_link.c | 4 |
1 files changed, 2 insertions, 2 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 c17db5c144aa..8dbf759eba45 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -3072,8 +3072,8 @@ 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 |