From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 18 Aug 2016 16:16:41 +0000 (+0100)
Subject: agp/intel: Flush chipset writes after updating a single PTE
X-Git-Tag: v4.8.9~36
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5e9e5cc8cd1db6105f543d1a667f0334f2ca679;p=thirdparty%2Fkernel%2Fstable.git

agp/intel: Flush chipset writes after updating a single PTE

commit 3497971a71d8b15a41b7bf2bf66ebf5909b2bd3f upstream.

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@tnsp.org>
Fixes: d6473f566417 ("drm/i915: Add support for mapping an object page...")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Tested-by: Matti Hämäläinen <ccr@tnsp.org>
Cc: drm-intel-fixes@lists.freedesktop.org
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160818161718.27187-2-chris@chris-wilson.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 44311296ec021..0f7d28a98b9a0 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);