Revision e3818697e1d9140d0b990fecf4429d40c41ca0b5 authored by Chris Wilson on 09 January 2017, 11:19:32 UTC, committed by Jani Nikula on 08 February 2017, 11:10:24 UTC
On a non-llc system, the objects are created with .cache_level =
CACHE_NONE and so the transition to uncached for scanout is a no-op.
However, if the object was never written to, it will still be in the CPU
domain (having been zeroed out by shmemfs). Those cachelines need to be
flushed prior to display.

Reported-and-tested-by: Vito Caputo
Fixes: a6a7cc4b7db6 ("drm/i915: Always flush the dirty CPU cache when pinning the scanout")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.10-rc1+
Link: http://patchwork.freedesktop.org/patch/msgid/20170109111932.6342-1-chris@chris-wilson.co.uk
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 69aeafeae9b30d797c439a30d1a4ccc8dc5b0eb0)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
1 parent 5351fbb
Raw File
lcm.c
#include <linux/compiler.h>
#include <linux/gcd.h>
#include <linux/export.h>
#include <linux/lcm.h>

/* Lowest common multiple */
unsigned long lcm(unsigned long a, unsigned long b)
{
	if (a && b)
		return (a / gcd(a, b)) * b;
	else
		return 0;
}
EXPORT_SYMBOL_GPL(lcm);

unsigned long lcm_not_zero(unsigned long a, unsigned long b)
{
	unsigned long l = lcm(a, b);

	if (l)
		return l;

	return (b ? : a);
}
EXPORT_SYMBOL_GPL(lcm_not_zero);
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