-void r300_emit_scissor_state(struct r300_context* r300,
- struct r300_scissor_state* scissor)
-{
- if (r300->rs_state->rs.scissor) {
- r300_emit_scissor_regs(r300, &scissor->scissor);
+ if (((struct r300_rs_state*)r300->rs_state.state)->rs.scissor) {
+ minx = MAX2(minx, scissor->minx);
+ miny = MAX2(miny, scissor->miny);
+ maxx = MIN2(maxx, scissor->maxx);
+ maxy = MIN2(maxy, scissor->maxy);
+ }
+
+ /* Special case for zero-area scissor.
+ *
+ * We can't allow the variables maxx and maxy to be zero because they are
+ * subtracted from later in the code, which would cause emitting ~0 and
+ * making the kernel checker angry.
+ *
+ * Let's consider we change maxx and maxy to 1, which is effectively
+ * a one-pixel area. We must then change minx and miny to a number which is
+ * greater than 1 to get the zero area back. */
+ if (!maxx || !maxy) {
+ minx = 2;
+ miny = 2;
+ maxx = 1;
+ maxy = 1;
+ }
+
+ if (r300screen->caps->is_r500) {
+ top_left =
+ (minx << R300_SCISSORS_X_SHIFT) |
+ (miny << R300_SCISSORS_Y_SHIFT);
+ bottom_right =
+ ((maxx - 1) << R300_SCISSORS_X_SHIFT) |
+ ((maxy - 1) << R300_SCISSORS_Y_SHIFT);