drm/amdgpu: Fix overflow of watermark calcs at > 4k resolutions.

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@gmail.com>
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Fixes: d63c277dc672 ("drm/amdgpu: Make display watermark calculations more accurate")
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
index 42448c7..db9b79a 100644 (file)
--- 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(struct amdgpu_device *adev,
        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) {

diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
index 904dabd..36d5128 100644 (file)
--- 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(struct amdgpu_device *adev,
        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) {

diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
index 6d02bdb..75689a2 100644 (file)
--- 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(struct amdgpu_device *adev,
        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;
 

diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
index b1fb601..ba2321e 100644 (file)
--- 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(struct amdgpu_device *adev,
        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) {