Finally fix the bit 17 swizzling code.

- pmap_kremove takes a va and a size, not a va range (unlike pmap_remove,
that gratuitious difference is nothing if not annoying).
- fix a memory leak of the bit 17 bitstring.
- fix the offset calculation when iterating through the dma segments.

Tested by Brandon Mercer, his machine now seems to be rock solid.

Remember kids, if a code path has not been tested fully, it does not work!

1 files changed, 12 insertions, 7 deletions

diff --git a/sys/dev/pci/drm/i915_drv.c b/sys/dev/pci/drm/i915_drv.c
index 91baf10270c..b3e2b61add3 100644
--- a/sys/dev/pci/drm/i915_drv.c
+++ b/sys/dev/pci/drm/i915_drv.c
@@ -3650,6 +3650,8 @@ i915_gem_free_object(struct drm_obj *obj)
 		i915_gem_object_unpin(obj);
 
 	i915_gem_object_unbind(obj, 0);
+	drm_free(obj_priv->bit_17);
+	obj_priv->bit_17 = NULL;
 	/* XXX dmatag went away? */
 }
 
@@ -4518,7 +4520,7 @@ inteldrm_swizzle_page(struct vm_page *pg)
 #if defined (__HAVE_PMAP_DIRECT)
 	pmap_unmap_direct(va);
 #else
-	pmap_kremove(va, va + PAGE_SIZE);
+	pmap_kremove(va, PAGE_SIZE);
 	pmap_update(pmap_kernel());
 	uvm_km_free(kernel_map, va, PAGE_SIZE);
 #endif
@@ -4534,12 +4536,14 @@ i915_gem_bit_17_swizzle(struct drm_obj *obj)
 	struct vm_page		*pg;
 	bus_dma_segment_t	*segp;
 	int			 page_count = obj->size >> PAGE_SHIFT;
-	int			 i = 0, n = 0, ret;
+	int                      i, n, ret;
 
 	if (dev_priv->mm.bit_6_swizzle_x != I915_BIT_6_SWIZZLE_9_10_17 ||
 	    obj_priv->bit_17 == NULL)
 		return;
 
+	segp = &obj_priv->dma_segs[0];
+	n = 0;
 	for (i = 0; i < page_count; i++) {
 		/* compare bit 17 with previous one (in case we swapped).
 		 * if they don't match we'll have to swizzle the page
@@ -4547,7 +4551,7 @@ i915_gem_bit_17_swizzle(struct drm_obj *obj)
 		if ((((segp->ds_addr + n) >> 17) & 0x1) !=
 		    test_bit(i, obj_priv->bit_17)) {
 			/* XXX move this to somewhere where we already have pg */
-			pg = PHYS_TO_VM_PAGE(segp->ds_addr + n * PAGE_SIZE);
+			pg = PHYS_TO_VM_PAGE(segp->ds_addr + n);
 			KASSERT(pg != NULL);
 			ret = inteldrm_swizzle_page(pg);
 			if (ret)
@@ -4555,7 +4559,8 @@ i915_gem_bit_17_swizzle(struct drm_obj *obj)
 			atomic_clearbits_int(&pg->pg_flags, PG_CLEAN);
 		}
 
-		if (++n * PAGE_SIZE > segp->ds_len) {
+		n += PAGE_SIZE;
+		if (n >= segp->ds_len) {
 			n = 0;
 			segp++;
 		}
@@ -4590,14 +4595,14 @@ i915_gem_save_bit_17_swizzle(struct drm_obj *obj)
 
 	segp = &obj_priv->dma_segs[0];
 	n = 0;
-	i = 0;
 	for (i = 0; i < page_count; i++) {
-		if ((segp->ds_addr + (n * PAGE_SIZE)) & (1 << 17))
+		if ((segp->ds_addr + n) & (1 << 17))
 			set_bit(i, obj_priv->bit_17);
 		else
 			clear_bit(i, obj_priv->bit_17);
 
-		if (++n * PAGE_SIZE > segp->ds_len) {
+		n += PAGE_SIZE;
+		if (n >= segp->ds_len) {
 			n = 0;
 			segp++;
 		}