This is a note to let you know that I've just added the patch titled drm/amdgpu: Fix overflow of watermark calcs at > 4k resolutions. to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amdgpu-fix-overflow-of-watermark-calcs-at-4k-resolutions.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From bea10413934dcf98cb9b2dfcdc56e1d28f192897 Mon Sep 17 00:00:00 2001 From: Mario Kleiner <mario.kleiner.de@xxxxxxxxx> Date: Tue, 13 Jun 2017 07:17:10 +0200 Subject: drm/amdgpu: Fix overflow of watermark calcs at > 4k resolutions. From: Mario Kleiner <mario.kleiner.de@xxxxxxxxx> commit bea10413934dcf98cb9b2dfcdc56e1d28f192897 upstream. Commit d63c277dc672e0 ("drm/amdgpu: 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@xxxxxxxxx> Reported-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> Fixes: d63c277dc672 ("drm/amdgpu: Make display watermark calculations more accurate") Cc: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> Cc: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/amd/amdgpu/dce_v10_0.c | 7 +++++-- drivers/gpu/drm/amd/amdgpu/dce_v11_0.c | 7 +++++-- drivers/gpu/drm/amd/amdgpu/dce_v6_0.c | 7 +++++-- drivers/gpu/drm/amd/amdgpu/dce_v8_0.c | 7 +++++-- 4 files changed, 20 insertions(+), 8 deletions(-) --- a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c +++ b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c @@ -1290,8 +1290,11 @@ static void dce_v10_0_program_watermarks u32 tmp, wm_mask, lb_vblank_lead_lines = 0; if (amdgpu_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); /* watermark for high clocks */ if (adev->pm.dpm_enabled) { --- a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c +++ b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c @@ -1257,8 +1257,11 @@ static void dce_v11_0_program_watermarks u32 tmp, wm_mask, lb_vblank_lead_lines = 0; if (amdgpu_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); /* watermark for high clocks */ if (adev->pm.dpm_enabled) { --- a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c +++ b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c @@ -1054,8 +1054,11 @@ static void dce_v6_0_program_watermarks( fixed20_12 a, b, c; if (amdgpu_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; --- a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c +++ b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c @@ -1211,8 +1211,11 @@ static void dce_v8_0_program_watermarks( u32 tmp, wm_mask, lb_vblank_lead_lines = 0; if (amdgpu_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); /* watermark for high clocks */ if (adev->pm.dpm_enabled) { Patches currently in stable-queue which might be from mario.kleiner.de@xxxxxxxxx are queue-4.9/drm-amdgpu-fix-overflow-of-watermark-calcs-at-4k-resolutions.patch