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Revision 20fa2ff0441eabc8e6263b428191228d9599ea9d authored by Leo (Sunpeng) Li on 29 May 2018, 13:51:51 UTC, committed by Alex Deucher on 29 May 2018, 19:22:28 UTC 
drm/amd/display: Fix BUG_ON during CRTC atomic check update
 
For cases where the CRTC is inactive (DPMS off), where a modeset is not
required, yet the CRTC is still in the atomic state, we should not
attempt to update anything on it.

Previously, we were relying on the modereset_required() helper to check
the above condition. However, the function returns false immediately if
a modeset is not required, ignoring the CRTC's enable/active state
flags. The correct way to filter is by looking at these flags instead.

Fixes: e277adc5a06c "drm/amd/display: Hookup color management functions"
Bugzilla: https://bugs.freedesktop.org/106194

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 parent 72777fe
Raw File
smp_processor_id.c 
// SPDX-License-Identifier: GPL-2.0
/*
 * lib/smp_processor_id.c
 *
 * DEBUG_PREEMPT variant of smp_processor_id().
 */
#include <linux/export.h>
#include <linux/sched.h>

notrace static unsigned int check_preemption_disabled(const char *what1,
							const char *what2)
{
	int this_cpu = raw_smp_processor_id();

	if (likely(preempt_count()))
		goto out;

	if (irqs_disabled())
		goto out;

	/*
	 * Kernel threads bound to a single CPU can safely use
	 * smp_processor_id():
	 */
	if (cpumask_equal(&current->cpus_allowed, cpumask_of(this_cpu)))
		goto out;

	/*
	 * It is valid to assume CPU-locality during early bootup:
	 */
	if (system_state < SYSTEM_SCHEDULING)
		goto out;

	/*
	 * Avoid recursion:
	 */
	preempt_disable_notrace();

	if (!printk_ratelimit())
		goto out_enable;

	printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n",
		what1, what2, preempt_count() - 1, current->comm, current->pid);

	printk("caller is %pS\n", __builtin_return_address(0));
	dump_stack();

out_enable:
	preempt_enable_no_resched_notrace();
out:
	return this_cpu;
}

notrace unsigned int debug_smp_processor_id(void)
{
	return check_preemption_disabled("smp_processor_id", "");
}
EXPORT_SYMBOL(debug_smp_processor_id);

notrace void __this_cpu_preempt_check(const char *op)
{
	check_preemption_disabled("__this_cpu_", op);
}
EXPORT_SYMBOL(__this_cpu_preempt_check);
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