https://github.com/torvalds/linux
Revision 98a226ed21949601b270f7ea20abc9f72f7b0be9 authored by Takashi Iwai on 10 June 2015, 08:27:00 UTC, committed by Takashi Iwai on 10 June 2015, 08:31:10 UTC
Along with the transition to regmap for managing the cached parameter
reads, the caps overwrite was also moved to regmap cache.  The cache
change itself works, but it still tries to write the non-existing verb
(the HDA parameter is read-only) wrongly.  It's harmless in most
cases, but some chips are picky and may result in the codec
communication stall.

This patch avoids it just by adding the missing flag check in
reg_write ops.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
1 parent 132bd96
Raw File
Tip revision: 98a226ed21949601b270f7ea20abc9f72f7b0be9 authored by Takashi Iwai on 10 June 2015, 08:27:00 UTC
ALSA: hda - Don't actually write registers for caps overwrites
Tip revision: 98a226e
up.c
/*
 * Uniprocessor-only support functions.  The counterpart to kernel/smp.c
 */

#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/smp.h>

int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
				int wait)
{
	unsigned long flags;

	WARN_ON(cpu != 0);

	local_irq_save(flags);
	func(info);
	local_irq_restore(flags);

	return 0;
}
EXPORT_SYMBOL(smp_call_function_single);

int smp_call_function_single_async(int cpu, struct call_single_data *csd)
{
	unsigned long flags;

	local_irq_save(flags);
	csd->func(csd->info);
	local_irq_restore(flags);
	return 0;
}
EXPORT_SYMBOL(smp_call_function_single_async);

int on_each_cpu(smp_call_func_t func, void *info, int wait)
{
	unsigned long flags;

	local_irq_save(flags);
	func(info);
	local_irq_restore(flags);
	return 0;
}
EXPORT_SYMBOL(on_each_cpu);

/*
 * Note we still need to test the mask even for UP
 * because we actually can get an empty mask from
 * code that on SMP might call us without the local
 * CPU in the mask.
 */
void on_each_cpu_mask(const struct cpumask *mask,
		      smp_call_func_t func, void *info, bool wait)
{
	unsigned long flags;

	if (cpumask_test_cpu(0, mask)) {
		local_irq_save(flags);
		func(info);
		local_irq_restore(flags);
	}
}
EXPORT_SYMBOL(on_each_cpu_mask);

/*
 * Preemption is disabled here to make sure the cond_func is called under the
 * same condtions in UP and SMP.
 */
void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
		      smp_call_func_t func, void *info, bool wait,
		      gfp_t gfp_flags)
{
	unsigned long flags;

	preempt_disable();
	if (cond_func(0, info)) {
		local_irq_save(flags);
		func(info);
		local_irq_restore(flags);
	}
	preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu_cond);
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