mirror of
https://github.com/torvalds/linux.git
synced 2024-12-27 05:11:48 +00:00
19244ad06b
This reverts commit cf450136bf.
It breaks reboot on at least one Thinkpad T43, as reported by Jörg Otte:
"On reboot it shuts down as normal.
The last lines displayed are:
>Unmounting temporary filesystems.. [OK]
>Deactivating swap... [OK]
>Unmounting local filesystems... [OK]
>Will now restart
> Restarting system
Then I hear it accessing the cd-drive, but then it's being stuck."
Jörg bisected the regression to this commit.
That commit fixes another machine (see
https://bugzilla.kernel.org/show_bug.cgi?id=11533
for details) that has a BIOS bug and doesn't support ACPI reset.
However, at least one of those other reporters no longer even has the
machine in question, and had a different workaround to begin with.
Besides, it clearly was a buggy BIOS. Let's not break the correct case
to fix that case.
Reported-and-bisected-by: Jörg Otte <jrg.otte@googlemail.com>
Cc: linux-acpi@vger.kernel.org
Cc: Len Brown <lenb@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
|
|
#include <linux/pci.h>
|
|
#include <linux/acpi.h>
|
|
#include <acpi/reboot.h>
|
|
|
|
void acpi_reboot(void)
|
|
{
|
|
struct acpi_generic_address *rr;
|
|
struct pci_bus *bus0;
|
|
u8 reset_value;
|
|
unsigned int devfn;
|
|
|
|
if (acpi_disabled)
|
|
return;
|
|
|
|
rr = &acpi_gbl_FADT.reset_register;
|
|
|
|
/* ACPI reset register was only introduced with v2 of the FADT */
|
|
|
|
if (acpi_gbl_FADT.header.revision < 2)
|
|
return;
|
|
|
|
/* Is the reset register supported? The spec says we should be
|
|
* checking the bit width and bit offset, but Windows ignores
|
|
* these fields */
|
|
if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER))
|
|
return;
|
|
|
|
reset_value = acpi_gbl_FADT.reset_value;
|
|
|
|
/* The reset register can only exist in I/O, Memory or PCI config space
|
|
* on a device on bus 0. */
|
|
switch (rr->space_id) {
|
|
case ACPI_ADR_SPACE_PCI_CONFIG:
|
|
/* The reset register can only live on bus 0. */
|
|
bus0 = pci_find_bus(0, 0);
|
|
if (!bus0)
|
|
return;
|
|
/* Form PCI device/function pair. */
|
|
devfn = PCI_DEVFN((rr->address >> 32) & 0xffff,
|
|
(rr->address >> 16) & 0xffff);
|
|
printk(KERN_DEBUG "Resetting with ACPI PCI RESET_REG.");
|
|
/* Write the value that resets us. */
|
|
pci_bus_write_config_byte(bus0, devfn,
|
|
(rr->address & 0xffff), reset_value);
|
|
break;
|
|
|
|
case ACPI_ADR_SPACE_SYSTEM_MEMORY:
|
|
case ACPI_ADR_SPACE_SYSTEM_IO:
|
|
printk(KERN_DEBUG "ACPI MEMORY or I/O RESET_REG.\n");
|
|
acpi_reset();
|
|
break;
|
|
}
|
|
}
|