https://github.com/torvalds/linux
Revision 8997b185119966c62c6e95e7b010b4060407e358 authored by Srivatsa S. Bhat on 28 April 2014, 18:54:58 UTC, committed by Rafael J. Wysocki on 28 April 2014, 23:22:54 UTC
During frequency transitions, the cpufreq core takes the responsibility of invoking cpufreq_freq_transition_begin() and cpufreq_freq_transition_end() for those cpufreq drivers that define the ->target_index callback but don't set the ASYNC_NOTIFICATION flag. The powernow-k7 cpufreq driver falls under this category, but this driver was invoking the _begin() and _end() APIs itself around frequency transitions, which led to double invocation of the _begin() API. The _begin API makes contending callers wait until the previous invocation is complete. Hence, the powernow-k7 driver ended up waiting on itself, leading to system hangs during boot. Fix this by removing the calls to the _begin() and _end() APIs from the powernow-k7 driver, since they rightly belong to the cpufreq core. Fixes: 12478cf0c55e (cpufreq: Make sure frequency transitions are serialized) Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
1 parent 3221e55
Tip revision: 8997b185119966c62c6e95e7b010b4060407e358 authored by Srivatsa S. Bhat on 28 April 2014, 18:54:58 UTC
cpufreq: powernow-k7: Fix double invocation of cpufreq_freq_transition_begin/end
cpufreq: powernow-k7: Fix double invocation of cpufreq_freq_transition_begin/end
Tip revision: 8997b18
soc-io.c
/*
* soc-io.c -- ASoC register I/O helpers
*
* Copyright 2009-2011 Wolfson Microelectronics PLC.
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/i2c.h>
#include <linux/spi/spi.h>
#include <linux/regmap.h>
#include <linux/export.h>
#include <sound/soc.h>
#include <trace/events/asoc.h>
#ifdef CONFIG_REGMAP
static int hw_write(struct snd_soc_codec *codec, unsigned int reg,
unsigned int value)
{
return regmap_write(codec->control_data, reg, value);
}
static unsigned int hw_read(struct snd_soc_codec *codec, unsigned int reg)
{
int ret;
unsigned int val;
ret = regmap_read(codec->control_data, reg, &val);
if (ret == 0)
return val;
else
return -1;
}
/**
* snd_soc_codec_set_cache_io: Set up standard I/O functions.
*
* @codec: CODEC to configure.
* @map: Register map to write to
*
* Register formats are frequently shared between many I2C and SPI
* devices. In order to promote code reuse the ASoC core provides
* some standard implementations of CODEC read and write operations
* which can be set up using this function.
*
* The caller is responsible for allocating and initialising the
* actual cache.
*
* Note that at present this code cannot be used by CODECs with
* volatile registers.
*/
int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
struct regmap *regmap)
{
int ret;
/* Device has made its own regmap arrangements */
if (!regmap)
codec->control_data = dev_get_regmap(codec->dev, NULL);
else
codec->control_data = regmap;
if (IS_ERR(codec->control_data))
return PTR_ERR(codec->control_data);
codec->write = hw_write;
codec->read = hw_read;
ret = regmap_get_val_bytes(codec->control_data);
/* Errors are legitimate for non-integer byte
* multiples */
if (ret > 0)
codec->val_bytes = ret;
codec->using_regmap = true;
return 0;
}
EXPORT_SYMBOL_GPL(snd_soc_codec_set_cache_io);
#else
int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
struct regmap *regmap)
{
return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(snd_soc_codec_set_cache_io);
#endif
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