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SubjectRe: [PATCH] More i2c driver changes for 2.5.70
I think there is a race condition here in the "set" functions.

I had added a down()/up() semaphore pair to the write clauses of the
functions in the pre-sysfs driver to prevent the xx_update_client() call
from modifying the cached values at the same time that the set_xxx()
function was trying to change them.

So for example:

> static ssize_t set_temp_max(struct device *dev, const char *buf,
> size_t count, int nr)
> {
> struct i2c_client *client = to_i2c_client(dev);
> struct lm85_data *data = i2c_get_clientdata(client);
>
> int val = simple_strtol(buf, NULL, 10);
> + down(&data->update_lock);
> data->temp_max[nr] = TEMP_TO_REG(val);
> lm85_write_value(client, LM85_REG_TEMP_MAX(nr),
> data->temp_max[nr]);
> + up(&data->update_lock);
> return count;
> }

Isn't that still needed?

:v)

Greg KH wrote:
> ChangeSet 1.1419.1.3, 2003/06/11 11:42:47-07:00, margitsw@t-online.de
>
> [PATCH] I2C: add LM85 driver
>
> Nothing extra in sysfs (yet) but I have left the way open in the driver
> to do this.
> Provides vid, vrm, fan_input(1-4), fan_min(1-4), pwm(1-3),
> pwm_enable(1-3), in_input(0-4), in_min(0-4), in_max(0-4),
> temp_input(1-3), temp_min(1-3), temp_max(1-3), alarms.
>
>
> drivers/i2c/chips/Kconfig | 19
> drivers/i2c/chips/Makefile | 1
> drivers/i2c/chips/lm85.c | 1223 +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 1241 insertions(+), 2 deletions(-)
>



> +static ssize_t show_temp_max(struct device *dev, char *buf, int nr)
> +{
> + struct i2c_client *client = to_i2c_client(dev);
> + struct lm85_data *data = i2c_get_clientdata(client);
> +
> + lm85_update_client(client);
> + return sprintf(buf,"%d\n", TEMP_FROM_REG(data->temp_max[nr]) );
> +}



> +static ssize_t set_temp_max(struct device *dev, const char *buf,
> + size_t count, int nr)
> +{
> + struct i2c_client *client = to_i2c_client(dev);
> + struct lm85_data *data = i2c_get_clientdata(client);
> +
> + int val = simple_strtol(buf, NULL, 10);
> + data->temp_max[nr] = TEMP_TO_REG(val);
> + lm85_write_value(client, LM85_REG_TEMP_MAX(nr), data->temp_max[nr]);
> + return count;
> +}


--
Philip Pokorny, Director of Engineering
Tel: 415-358-2635 Fax: 415-358-2646 Toll Free: 888-PENGUIN
PENGUIN COMPUTING, INC.
www.penguincomputing.com

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