Mesa (master): svga: clamp device line width to at least 1 to fix HWv8 line stippling

[Brian Paul]

Module: Mesa
Branch: master
Commit: c2b92dada076afc303e31e3d029256d234254c27
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=c2b92dada076afc303e31e3d029256d234254c27

Author: Brian Paul <brianp at vmware.com>
Date:   Thu Jun 15 11:31:53 2017 -0600

svga: clamp device line width to at least 1 to fix HWv8 line stippling

The line stipple fallback code for virtual HW version 8 didn't work.

With HW version 8, we were getting zero when querying the max line
widths (AA and non-AA).  This means we were setting the draw module's
wide line threshold to zero.  This caused the wide line stage to always
get enabled.  That caused the line stipple module to fall because the
wide line stage was clobbering the rasterization state with a state
object setting the line stipple pattern to 0xffff.

Now the wide_lines variable in draw's validate_pipeline() will not
be incorrectly set.

Also improve debug output.

BTW, also this fixes several other piglit tests: polygon-mode,
primitive- restart-draw-mode, and line-flat-clip-color since they
all use the draw module fallback.

See VMware bug 1895811.

Reviewed-by: Charmaine Lee <charmainel at vmware.com>

---

 src/gallium/drivers/svga/svga_screen.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/gallium/drivers/svga/svga_screen.c b/src/gallium/drivers/svga/svga_screen.c
index 202f54f8ad..3aa99452a8 100644
--- a/src/gallium/drivers/svga/svga_screen.c
+++ b/src/gallium/drivers/svga/svga_screen.c
@@ -1142,18 +1142,18 @@ svga_screen_create(struct svga_winsys_screen *sws)
       get_bool_cap(sws, SVGA3D_DEVCAP_LINE_STIPPLE, FALSE);
 
    svgascreen->maxLineWidth =
-      get_float_cap(sws, SVGA3D_DEVCAP_MAX_LINE_WIDTH, 1.0f);
+      MAX2(1.0, get_float_cap(sws, SVGA3D_DEVCAP_MAX_LINE_WIDTH, 1.0f));
 
    svgascreen->maxLineWidthAA =
-      get_float_cap(sws, SVGA3D_DEVCAP_MAX_AA_LINE_WIDTH, 1.0f);
+      MAX2(1.0, get_float_cap(sws, SVGA3D_DEVCAP_MAX_AA_LINE_WIDTH, 1.0f));
 
    if (0) {
       debug_printf("svga: haveProvokingVertex %u\n",
                    svgascreen->haveProvokingVertex);
       debug_printf("svga: haveLineStip %u  "
-                   "haveLineSmooth %u  maxLineWidth %f\n",
+                   "haveLineSmooth %u  maxLineWidth %.2f  maxLineWidthAA %.2f\n",
                    svgascreen->haveLineStipple, svgascreen->haveLineSmooth,
-                   svgascreen->maxLineWidth);
+                   svgascreen->maxLineWidth, svgascreen->maxLineWidthAA);
       debug_printf("svga: maxPointSize %g\n", svgascreen->maxPointSize);
       debug_printf("svga: msaa samples mask: 0x%x\n", svgascreen->ms_samples);
    }