Commit f0e2f38b authored by Francisco Jerez's avatar Francisco Jerez Committed by Dave Airlie
Browse files

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: default avatarDave Airlie <airlied@redhat.com>
parent 6a660f06

drivers/gpu/drm/ttm/ttm_tt.c

+11 −7
Original line number Diff line number Diff line
@@ -196,14 +196,15 @@ EXPORT_SYMBOL(ttm_tt_populate); 


#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 @@ static inline int ttm_tt_set_page_caching(struct page *p, 
			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 @@ static int ttm_tt_set_caching(struct ttm_tt *ttm, 
	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 @@ out_err: 
	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);

		}

	}

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