[PATCH 4.4 030/103] drm/amdgpu: Make display watermark calculations more accurate

From: Greg Kroah-Hartman
Date: Tue May 23 2017 - 16:53:00 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Mario Kleiner <mario.kleiner.de@xxxxxxxxx>

commit d63c277dc672e0c568481af043359420fa9d4736 upstream.

Avoid big roundoff errors in scanline/hactive durations for
high pixel clocks, especially for >= 500 Mhz, and thereby
program more accurate display fifo watermarks.

Implemented here for DCE 6,8,10,11.
Successfully tested on DCE 10 with AMD R9 380 Tonga.

Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Mario Kleiner <mario.kleiner.de@xxxxxxxxx>
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 | 10 +++++-----
drivers/gpu/drm/amd/amdgpu/dce_v11_0.c | 10 +++++-----
drivers/gpu/drm/amd/amdgpu/dce_v8_0.c | 10 +++++-----
3 files changed, 15 insertions(+), 15 deletions(-)

--- a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
@@ -1237,14 +1237,14 @@ static void dce_v10_0_program_watermarks
{
struct drm_display_mode *mode = &amdgpu_crtc->base.mode;
struct dce10_wm_params wm_low, wm_high;
- u32 pixel_period;
+ u32 active_time;
u32 line_time = 0;
u32 latency_watermark_a = 0, latency_watermark_b = 0;
u32 tmp, wm_mask, lb_vblank_lead_lines = 0;

if (amdgpu_crtc->base.enabled && num_heads && mode) {
- pixel_period = 1000000 / (u32)mode->clock;
- line_time = min((u32)mode->crtc_htotal * pixel_period, (u32)65535);
+ active_time = 1000000UL * (u32)mode->crtc_hdisplay / (u32)mode->clock;
+ line_time = min((u32) (1000000UL * (u32)mode->crtc_htotal / (u32)mode->clock), (u32)65535);

/* watermark for high clocks */
if (adev->pm.dpm_enabled) {
@@ -1259,7 +1259,7 @@ static void dce_v10_0_program_watermarks

wm_high.disp_clk = mode->clock;
wm_high.src_width = mode->crtc_hdisplay;
- wm_high.active_time = mode->crtc_hdisplay * pixel_period;
+ wm_high.active_time = active_time;
wm_high.blank_time = line_time - wm_high.active_time;
wm_high.interlaced = false;
if (mode->flags & DRM_MODE_FLAG_INTERLACE)
@@ -1298,7 +1298,7 @@ static void dce_v10_0_program_watermarks

wm_low.disp_clk = mode->clock;
wm_low.src_width = mode->crtc_hdisplay;
- wm_low.active_time = mode->crtc_hdisplay * pixel_period;
+ wm_low.active_time = active_time;
wm_low.blank_time = line_time - wm_low.active_time;
wm_low.interlaced = false;
if (mode->flags & DRM_MODE_FLAG_INTERLACE)
--- a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
@@ -1225,14 +1225,14 @@ static void dce_v11_0_program_watermarks
{
struct drm_display_mode *mode = &amdgpu_crtc->base.mode;
struct dce10_wm_params wm_low, wm_high;
- u32 pixel_period;
+ u32 active_time;
u32 line_time = 0;
u32 latency_watermark_a = 0, latency_watermark_b = 0;
u32 tmp, wm_mask, lb_vblank_lead_lines = 0;

if (amdgpu_crtc->base.enabled && num_heads && mode) {
- pixel_period = 1000000 / (u32)mode->clock;
- line_time = min((u32)mode->crtc_htotal * pixel_period, (u32)65535);
+ active_time = 1000000UL * (u32)mode->crtc_hdisplay / (u32)mode->clock;
+ line_time = min((u32) (1000000UL * (u32)mode->crtc_htotal / (u32)mode->clock), (u32)65535);

/* watermark for high clocks */
if (adev->pm.dpm_enabled) {
@@ -1247,7 +1247,7 @@ static void dce_v11_0_program_watermarks

wm_high.disp_clk = mode->clock;
wm_high.src_width = mode->crtc_hdisplay;
- wm_high.active_time = mode->crtc_hdisplay * pixel_period;
+ wm_high.active_time = active_time;
wm_high.blank_time = line_time - wm_high.active_time;
wm_high.interlaced = false;
if (mode->flags & DRM_MODE_FLAG_INTERLACE)
@@ -1286,7 +1286,7 @@ static void dce_v11_0_program_watermarks

wm_low.disp_clk = mode->clock;
wm_low.src_width = mode->crtc_hdisplay;
- wm_low.active_time = mode->crtc_hdisplay * pixel_period;
+ wm_low.active_time = active_time;
wm_low.blank_time = line_time - wm_low.active_time;
wm_low.interlaced = false;
if (mode->flags & DRM_MODE_FLAG_INTERLACE)
--- a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
@@ -1207,14 +1207,14 @@ static void dce_v8_0_program_watermarks(
{
struct drm_display_mode *mode = &amdgpu_crtc->base.mode;
struct dce8_wm_params wm_low, wm_high;
- u32 pixel_period;
+ u32 active_time;
u32 line_time = 0;
u32 latency_watermark_a = 0, latency_watermark_b = 0;
u32 tmp, wm_mask, lb_vblank_lead_lines = 0;

if (amdgpu_crtc->base.enabled && num_heads && mode) {
- pixel_period = 1000000 / (u32)mode->clock;
- line_time = min((u32)mode->crtc_htotal * pixel_period, (u32)65535);
+ active_time = 1000000UL * (u32)mode->crtc_hdisplay / (u32)mode->clock;
+ line_time = min((u32) (1000000UL * (u32)mode->crtc_htotal / (u32)mode->clock), (u32)65535);

/* watermark for high clocks */
if (adev->pm.dpm_enabled) {
@@ -1229,7 +1229,7 @@ static void dce_v8_0_program_watermarks(

wm_high.disp_clk = mode->clock;
wm_high.src_width = mode->crtc_hdisplay;
- wm_high.active_time = mode->crtc_hdisplay * pixel_period;
+ wm_high.active_time = active_time;
wm_high.blank_time = line_time - wm_high.active_time;
wm_high.interlaced = false;
if (mode->flags & DRM_MODE_FLAG_INTERLACE)
@@ -1268,7 +1268,7 @@ static void dce_v8_0_program_watermarks(

wm_low.disp_clk = mode->clock;
wm_low.src_width = mode->crtc_hdisplay;
- wm_low.active_time = mode->crtc_hdisplay * pixel_period;
+ wm_low.active_time = active_time;
wm_low.blank_time = line_time - wm_low.active_time;
wm_low.interlaced = false;
if (mode->flags & DRM_MODE_FLAG_INTERLACE)