drm/i915: fix the wrong latency value while computing wm0
On Ironlake, the LP0 latency is hardcoded and in ns unit, while on
Sandybridge, it comes from a register and with unit 0.1 us. So, fix
the wrong latency value while computing wm0 on Ironlake and Sandybridge.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 79753b8..75c433e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3418,9 +3418,9 @@
static bool ironlake_compute_wm0(struct drm_device *dev,
int pipe,
const struct intel_watermark_params *display,
- int display_latency,
+ int display_latency_ns,
const struct intel_watermark_params *cursor,
- int cursor_latency,
+ int cursor_latency_ns,
int *plane_wm,
int *cursor_wm)
{
@@ -3438,7 +3438,7 @@
pixel_size = crtc->fb->bits_per_pixel / 8;
/* Use the small buffer method to calculate plane watermark */
- entries = ((clock * pixel_size / 1000) * display_latency * 100) / 1000;
+ entries = ((clock * pixel_size / 1000) * display_latency_ns) / 1000;
entries = DIV_ROUND_UP(entries, display->cacheline_size);
*plane_wm = entries + display->guard_size;
if (*plane_wm > (int)display->max_wm)
@@ -3446,7 +3446,7 @@
/* Use the large buffer method to calculate cursor watermark */
line_time_us = ((htotal * 1000) / clock);
- line_count = (cursor_latency * 100 / line_time_us + 1000) / 1000;
+ line_count = (cursor_latency_ns / line_time_us + 1000) / 1000;
entries = line_count * 64 * pixel_size;
entries = DIV_ROUND_UP(entries, cursor->cacheline_size);
*cursor_wm = entries + cursor->guard_size;
@@ -3644,7 +3644,7 @@
int pixel_size)
{
struct drm_i915_private *dev_priv = dev->dev_private;
- int latency = SNB_READ_WM0_LATENCY();
+ int latency = SNB_READ_WM0_LATENCY() * 100; /* In unit 0.1us */
int fbc_wm, plane_wm, cursor_wm, enabled;
int clock;