drm/ttm: fix caching problem on non-PAT systems.
http://bugzilla.kernel.org/show_bug.cgi?id=15328
This fixes a serious regression on AGP/non-PAT systems, where
pages were ending up in the wrong state and slowing down the
whole system.
[airlied: taken this from the bug as the other option is to revert
the change which caused it].
Tested-by: John W. Linville (in bug).
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index e2123af..3d47a2c 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -196,14 +196,15 @@
#ifdef CONFIG_X86
static inline int ttm_tt_set_page_caching(struct page *p,
- enum ttm_caching_state c_state)
+ enum ttm_caching_state c_old,
+ enum ttm_caching_state c_new)
{
int ret = 0;
if (PageHighMem(p))
return 0;
- if (get_page_memtype(p) != -1) {
+ if (c_old != tt_cached) {
/* p isn't in the default caching state, set it to
* writeback first to free its current memtype. */
@@ -212,16 +213,17 @@
return ret;
}
- if (c_state == tt_wc)
+ if (c_new == tt_wc)
ret = set_memory_wc((unsigned long) page_address(p), 1);
- else if (c_state == tt_uncached)
+ else if (c_new == tt_uncached)
ret = set_pages_uc(p, 1);
return ret;
}
#else /* CONFIG_X86 */
static inline int ttm_tt_set_page_caching(struct page *p,
- enum ttm_caching_state c_state)
+ enum ttm_caching_state c_old,
+ enum ttm_caching_state c_new)
{
return 0;
}
@@ -254,7 +256,9 @@
for (i = 0; i < ttm->num_pages; ++i) {
cur_page = ttm->pages[i];
if (likely(cur_page != NULL)) {
- ret = ttm_tt_set_page_caching(cur_page, c_state);
+ ret = ttm_tt_set_page_caching(cur_page,
+ ttm->caching_state,
+ c_state);
if (unlikely(ret != 0))
goto out_err;
}
@@ -268,7 +272,7 @@
for (j = 0; j < i; ++j) {
cur_page = ttm->pages[j];
if (likely(cur_page != NULL)) {
- (void)ttm_tt_set_page_caching(cur_page,
+ (void)ttm_tt_set_page_caching(cur_page, c_state,
ttm->caching_state);
}
}