On Tue, 05 Apr 2011 18:02:51 -0700, Keith Packard <[email protected]> wrote:
> On Tue, 05 Apr 2011 22:12:19 +0100, Chris Wilson <[email protected]>
> wrote:
>
> > Indeed, I started by setting them to zero in the caller. Decided that
> > there was some precedent to use the guard_size as the minimum value for
> > unused planes (and so perhaps the unused planes on the unused pipes) and
> > so it was then natural to do it inside g4x_compute_wm. I guess it all
> > depends on how many FIFOs are split between the pipes. Using guard_size,
> > I believe, should be safest.
>
> guard_size is probably better than random stack stuff. Any opinion on
> whether this should be done in g4x_update_wm instead of g4x_compute_wm0?
I'd prefer to keep the mucking around with intel_watermak_params in the
one spot. How about:
diff --git a/drivers/gpu/drm/i915/intel_display.c
b/drivers/gpu/drm/i915/intel_display.c
index f1798f2..dbe11eb 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3799,11 +3799,14 @@ static bool g4x_compute_wm0(struct drm_device *dev,
int line_time_us, line_count;
int entries, tlb_miss;
+ /* The FIFO requires a minimum number of entries (the guard size)
+ * as it switches between planes:
+ */
+ *cursor_wm = cursor->guard_size;
+ *plane_wm = display->guard_size;
+
crtc = intel_get_crtc_for_plane(dev, plane);
- if (crtc->fb == NULL || !crtc->enabled) {
- *cursor_wm = *plane_wm = display->guard_size;
+ if (crtc->fb == NULL || !crtc->enabled)
return false;
- }
htotal = crtc->mode.htotal;
hdisplay = crtc->mode.hdisplay;
@@ -3816,7 +3819,7 @@ static bool g4x_compute_wm0(struct drm_device *dev,
if (tlb_miss > 0)
entries += tlb_miss;
entries = DIV_ROUND_UP(entries, display->cacheline_size);
- *plane_wm = entries + display->guard_size;
+ *plane_wm += entries;
if (*plane_wm > (int)display->max_wm)
*plane_wm = display->max_wm;
@@ -3828,7 +3831,7 @@ static bool g4x_compute_wm0(struct drm_device *dev,
if (tlb_miss > 0)
entries += tlb_miss;
entries = DIV_ROUND_UP(entries, cursor->cacheline_size);
- *cursor_wm = entries + cursor->guard_size;
+ *cursor_wm += entries;
if (*cursor_wm > (int)cursor->max_wm)
*cursor_wm = (int)cursor->max_wm;
--
Chris Wilson, Intel Open Source Technology Centre
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