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authorMario Kleiner <mario.kleiner.de@gmail.com>2017-06-13 07:17:11 +0200
committerAlex Deucher <alexander.deucher@amd.com>2017-06-14 09:25:58 -0400
commit55f61a040e1b1ea0ba962e53ae341b4c51915bd1 (patch)
tree16528c7a73bc73fc1fc4aec5046d3c21adec60da /drivers/gpu/drm/radeon/evergreen.c
parentbea10413934dcf98cb9b2dfcdc56e1d28f192897 (diff)
downloadlinux-55f61a040e1b1ea0ba962e53ae341b4c51915bd1.tar.gz
drm/radeon: Fix overflow of watermark calcs at > 4k resolutions.
Commit e6b9a6c84b93
("drm/radeon: Make display watermark calculations more accurate")
made watermark calculations more accurate, but not for > 4k
resolutions on 32-Bit architectures, as it introduced an integer
overflow for those setups and resolutions.

Fix this by proper u64 casting and division.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Fixes: e6b9a6c84b93 ("drm/radeon: Make display watermark calculations more accurate")
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
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.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index 0bf103536404..534637203e70 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -2266,8 +2266,11 @@ static void evergreen_program_watermarks(struct radeon_device *rdev,
 	fixed20_12 a, b, c;
 
 	if (radeon_crtc->base.enabled && num_heads && mode) {
-		active_time = 1000000UL * (u32)mode->crtc_hdisplay / (u32)mode->clock;
-		line_time = min((u32) (1000000UL * (u32)mode->crtc_htotal / (u32)mode->clock), (u32)65535);
+		active_time = (u32) div_u64((u64)mode->crtc_hdisplay * 1000000,
+					    (u32)mode->clock);
+		line_time = (u32) div_u64((u64)mode->crtc_htotal * 1000000,
+					  (u32)mode->clock);
+		line_time = min(line_time, (u32)65535);
 		priority_a_cnt = 0;
 		priority_b_cnt = 0;
 		dram_channels = evergreen_get_number_of_dram_channels(rdev);