Patch "agp/intel: Flush chipset writes after updating a single PTE" has been added to the 4.8-stable tree

Patch "agp/intel: Flush chipset writes after updating a single PTE" has been added to the 4.8-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

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

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     agp-intel-flush-chipset-writes-after-updating-a-single-pte.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 3497971a71d8b15a41b7bf2bf66ebf5909b2bd3f Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 18 Aug 2016 17:16:41 +0100
Subject: agp/intel: Flush chipset writes after updating a single PTE
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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From: Chris Wilson <chris@chris-wilson.co.uk>

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>

---
 drivers/char/agp/intel-gtt.c |    2 ++
 1 file changed, 2 insertions(+)

--- 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 ad
 			   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);
 


Patches currently in stable-queue which might be from chris@chris-wilson.co.uk are

queue-4.8/agp-intel-flush-chipset-writes-after-updating-a-single-pte.patch