On Wed, Mar 5, 2014 at 2:38 AM, Daniel Vetter <daniel@xxxxxxxx> wrote:
> On Tue, Mar 04, 2014 at 05:06:22PM +0200, Ville Syrjälä wrote:
>> On Tue, Mar 04, 2014 at 10:38:58PM +0800, Chia-I Wu wrote:
>> > On Tue, Mar 4, 2014 at 5:41 PM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
>> > > This reverts commit 116f2b6da868dec7539103574d0421cd6221e931.
>> > >
>> > > This optimization causes widespread corruption in games, and even in
>> > > glxgears, on my ivb:gt1. The corruption appears like z-fighting of
>> > > overlapping polygons in the HiZ buffer.
>> > >
>> > > The observation ties in very closely with the description of the
>> > > optimization disabled by default on IVB:
>> > >
>> > > "The Hierarchical Z RAW Stall Optimization allows non-overlapping
>> > > polygons in the same 8x4 pixel/sample area to be processed without
>> > > stalling waiting for the earlier ones to write to Hierarchical Z
>> > > buffer."
>> > >
>> > > No reason is given for why it is disabled by default, usually for such
>> > > optimizations it is that it is incomplete. However, there is no
>> > > indication whether this a gt1 only issue either. Before considering
>> > > reenabling this optimization, I would first suggest reproducing the
>> > > corruption in piglit.
>> > I wonder if Haswell GT1 is affected too (that's in another commit). I
>> > do not own a GT1 for either GEN to verify the issue or to create a
>> > sensible piglit test.
>>
>> I'm seeing corruption on IVB GT2 as well. I might be more blind than
>> Chris or it's less subtle on GT2 since it took me a while to spot it.
>> Seems to be easiest to spot in Epic citadel when you go inside the
>> temple. I can't spot the same corruption on HSW GT3.
>
> Queued for -next, thanks for the patch. We can tackle hsw when that on
> blows up ...
I've created a simple demo that demonstrates the problem on IVB GT2,
FWIW. The patch is against mesa-demos. Not sure if there is a need
to make it a piglit test.
> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
olv@xxxxxxxxxx
From 00f78fa9c2162e97ff89e9131c53c7f7cd557949 Mon Sep 17 00:00:00 2001
From: Chia-I Wu <olvaffe@xxxxxxxxx>
Date: Wed, 12 Mar 2014 15:12:43 +0800
Subject: [PATCH] ivb-hiz: demonstrate hiz depth stall opt bug on IVB
---
src/demos/Makefile.am | 1 +
src/demos/ivb-hiz.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 111 insertions(+)
create mode 100644 src/demos/ivb-hiz.c
diff --git a/src/demos/Makefile.am b/src/demos/Makefile.am
index 41603fa..2333476 100644
--- a/src/demos/Makefile.am
+++ b/src/demos/Makefile.am
@@ -32,6 +32,7 @@ AM_LDFLAGS = \
if HAVE_GLUT
bin_PROGRAMS = \
+ ivb-hiz \
arbfplight \
arbfslight \
arbocclude \
diff --git a/src/demos/ivb-hiz.c b/src/demos/ivb-hiz.c
new file mode 100644
index 0000000..0404d80
--- /dev/null
+++ b/src/demos/ivb-hiz.c
@@ -0,0 +1,110 @@
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "glut_wrap.h"
+
+static GLfloat radius = 0.7f;
+static GLboolean grid = GL_FALSE;
+static int win_width, win_height;
+
+static void
+draw(void)
+{
+ const int num_triangles = 100;
+ const GLfloat delta = M_PI / 2.0f / num_triangles;
+ int i;
+
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+ glBegin(GL_TRIANGLE_FAN);
+ glColor3f(1.0, 1.0, 1.0);
+ glVertex2f(0.0f, 1.0f);
+ glVertex2f(radius, 1.0f);
+ for (i = 1; i <= num_triangles; i++) {
+ GLfloat angle = i * delta;
+ glVertex2f(radius * cos(angle), 1.0f - radius * sin(angle));
+ }
+ glEnd();
+
+ if (grid) {
+ glDisable(GL_DEPTH_TEST);
+ glColor3f(1.0, 0.0, 0.0);
+
+ glPushMatrix();
+ glLoadIdentity();
+ glBegin(GL_LINES);
+
+ for (i = 0; 8 * i < win_width; i++) {
+ glVertex2f(8 * i + 0.5f, 0.0f);
+ glVertex2f(8 * i + 0.5f, win_height);
+ }
+
+ for (i = 0; 8 * i < win_height; i++) {
+ glVertex2f(0.0f, win_height - 8 * i - 0.5f);
+ glVertex2f(win_width, win_height - 8 * i - 0.5f);
+ }
+
+ glEnd();
+ glPopMatrix();
+ glEnable(GL_DEPTH_TEST);
+ }
+
+ glutSwapBuffers();
+ glutPostRedisplay();
+}
+
+static void
+key(unsigned char k, int x, int y)
+{
+ switch (k) {
+ case 'r':
+ radius -= 0.01f;
+ break;
+ case 'R':
+ radius += 0.01f;
+ break;
+ case 'g':
+ grid = !grid;
+ break;
+ case 27: /* Escape */
+ exit(0);
+ }
+}
+
+static void
+reshape(int width, int height)
+{
+ glViewport(0, 0, width, height);
+
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(0.0, width, 0.0, height, 1.0, -1.0);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+
+ glScalef(width, height, 1.0f);
+
+ win_width = width;
+ win_height = height;
+}
+
+int main(int argc, char *argv[])
+{
+ glutInitWindowSize(400, 400);
+ glutInit(&argc, argv);
+
+ glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);
+
+ glutCreateWindow("HiZ");
+
+ glEnable(GL_DEPTH_TEST);
+ //glDepthFunc(GL_LEQUAL);
+
+ glutDisplayFunc(draw);
+ glutReshapeFunc(reshape);
+ glutKeyboardFunc(key);
+
+ glutMainLoop();
+ return 0; /* ANSI C requires main to return int. */
+}
--
1.8.3.1
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
