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| author | Mario Kleiner <mario.kleiner.de@gmail.com> | 2017-04-24 02:33:08 +0300 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2017-04-29 00:33:03 +0300 |
| commit | ae45bbc2ba8f92b5a773fece6f5792f497c89282 (patch) | |
| tree | 18464c5502b6fcca42218b81296436221c04a8a1 /drivers/gpu/drm/radeon/evergreen.c | |
| parent | effaf848b957fbf72a3b6a1ad87f5e031eda0b75 (diff) | |
| download | linux-ae45bbc2ba8f92b5a773fece6f5792f497c89282.tar.xz | |
drm/radeon: Avoid overflows/divide-by-zero in latency_watermark calculations.
At dot clocks > approx. 250 Mhz, some of these calcs will overflow and
cause miscalculation of latency watermarks, and for some overflows also
divide-by-zero driver crash. Make calcs more overflow resistant.
This is a direct port of the corresponding patch from amdgpu-kms,
copy-paste for cik from dce-8 and si from dce-6, with a slightly
simpler variant for evergreen dce-4/5.
Only tested on DCE-4 evergreen with a Radeon HD-5770.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/radeon/evergreen.c')
| -rw-r--r-- | drivers/gpu/drm/radeon/evergreen.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c index d1b1e0cc3c25..3c9c133bcccc 100644 --- a/drivers/gpu/drm/radeon/evergreen.c +++ b/drivers/gpu/drm/radeon/evergreen.c @@ -2188,13 +2188,7 @@ static u32 evergreen_latency_watermark(struct evergreen_wm_params *wm) b.full = dfixed_const(wm->num_heads); a.full = dfixed_div(a, b); - b.full = dfixed_const(1000); - c.full = dfixed_const(wm->disp_clk); - b.full = dfixed_div(c, b); - c.full = dfixed_const(wm->bytes_per_pixel); - b.full = dfixed_mul(b, c); - - lb_fill_bw = min(dfixed_trunc(a), dfixed_trunc(b)); + lb_fill_bw = min(dfixed_trunc(a), wm->disp_clk * wm->bytes_per_pixel / 1000); a.full = dfixed_const(max_src_lines_per_dst_line * wm->src_width * wm->bytes_per_pixel); b.full = dfixed_const(1000); |