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
dump_stack.c
/*
* Provide a default dump_stack() function for architectures
* which don't implement their own.
*/
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/atomic.h>
static void __dump_stack(void)
{
dump_stack_print_info(KERN_DEFAULT);
show_stack(NULL, NULL);
}
/**
* dump_stack - dump the current task information and its stack trace
*
* Architectures can override this implementation by implementing its own.
*/
#ifdef CONFIG_SMP
static atomic_t dump_lock = ATOMIC_INIT(-1);
asmlinkage __visible void dump_stack(void)
{
unsigned long flags;
int was_locked;
int old;
int cpu;
/*
* Permit this cpu to perform nested stack dumps while serialising
* against other CPUs
*/
retry:
local_irq_save(flags);
cpu = smp_processor_id();
old = atomic_cmpxchg(&dump_lock, -1, cpu);
if (old == -1) {
was_locked = 0;
} else if (old == cpu) {
was_locked = 1;
} else {
local_irq_restore(flags);
cpu_relax();
goto retry;
}
__dump_stack();
if (!was_locked)
atomic_set(&dump_lock, -1);
local_irq_restore(flags);
}
#else
asmlinkage __visible void dump_stack(void)
{
__dump_stack();
}
#endif
EXPORT_SYMBOL(dump_stack);
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