[Intel-gfx] [PATCH] agp/intel: Flush chipset writes after updating a single PTE

[Chris Wilson]

After we update one PTE for a page, the caller expects to be able to
immediately use that through a GGTT read/write. To comply with the
callers expectations we therefore need to flush the chipset buffers
before returning.

Reported-by: Matti Hämäläinen <ccr at tnsp.org>
Fixes: d6473f566417 ("drm/i915: Add support for mapping an object page...")
Cc: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Tested-by: Matti Hämäläinen <ccr at tnsp.org>
Cc: drm-intel-fixes at lists.freedesktop.org
---
 drivers/char/agp/intel-gtt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 44311296ec02..0f7d28a98b9a 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -845,6 +845,8 @@ void intel_gtt_insert_page(dma_addr_t addr,
 			   unsigned int flags)
 {
 	intel_private.driver->write_entry(addr, pg, flags);
+	if (intel_private.driver->chipset_flush)
+		intel_private.driver->chipset_flush();
 }
 EXPORT_SYMBOL(intel_gtt_insert_page);
 
-- 
2.8.1