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Revision 1fd684346d41f6be2487c161f60d03a7feb68911 authored by Rafael J. Wysocki on 19 January 2009, 19:57:36 UTC, committed by Jeff Garzik on 27 January 2009, 07:15:51 UTC 
SATA AHCI: Blacklist system that spins off disks during ACPI power off
 
Some notebooks from HP have the problem that their BIOSes attempt to
spin down hard drives before entering ACPI system states S4 and S5.
This leads to a yo-yo effect during system power-off shutdown and the
last phase of hibernation when the disk is first spun down by the
kernel and then almost immediately turned on and off by the BIOS.
This, in turn, may result in shortening the disk's life times.

To prevent this from happening we can blacklist the affected systems
using DMI information.

Blacklist HP nx6310 that uses the AHCI driver.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
1 parent 2a6e58d
Raw File
string_helpers.c 
/*
 * Helpers for formatting and printing strings
 *
 * Copyright 31 August 2008 James Bottomley
 */
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/string_helpers.h>

/**
 * string_get_size - get the size in the specified units
 * @size:	The size to be converted
 * @units:	units to use (powers of 1000 or 1024)
 * @buf:	buffer to format to
 * @len:	length of buffer
 *
 * This function returns a string formatted to 3 significant figures
 * giving the size in the required units.  Returns 0 on success or
 * error on failure.  @buf is always zero terminated.
 *
 */
int string_get_size(u64 size, const enum string_size_units units,
		    char *buf, int len)
{
	const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
				   "EB", "ZB", "YB", NULL};
	const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
				 "EiB", "ZiB", "YiB", NULL };
	const char **units_str[] = {
		[STRING_UNITS_10] =  units_10,
		[STRING_UNITS_2] = units_2,
	};
	const unsigned int divisor[] = {
		[STRING_UNITS_10] = 1000,
		[STRING_UNITS_2] = 1024,
	};
	int i, j;
	u64 remainder = 0, sf_cap;
	char tmp[8];

	tmp[0] = '\0';
	i = 0;
	if (size >= divisor[units]) {
		while (size >= divisor[units] && units_str[units][i]) {
			remainder = do_div(size, divisor[units]);
			i++;
		}

		sf_cap = size;
		for (j = 0; sf_cap*10 < 1000; j++)
			sf_cap *= 10;

		if (j) {
			remainder *= 1000;
			do_div(remainder, divisor[units]);
			snprintf(tmp, sizeof(tmp), ".%03lld",
				 (unsigned long long)remainder);
			tmp[j+1] = '\0';
		}
	}

	snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
		 tmp, units_str[units][i]);

	return 0;
}
EXPORT_SYMBOL(string_get_size);
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