2005-11-27 13:57:31

by Daniel Drake

[permalink] [raw]
Subject: [PATCH] ACPI scan: Revert acpi_bus_find_driver() return value check

2.6.13 introduced a change to drivers/acpi/scan.c along the lines of:

*
* TBD: Assumes LDM provides driver hot-plug capability.
*/
- result = acpi_bus_find_driver(device);
+ acpi_bus_find_driver(device);

end:
if (!result)

This was inside this commit:
http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=3fb02738b0fd36f47710a2bf207129efd2f5daa2

Since then, various HP/Compaq laptops have not been able to boot, freezing
after these messages:

PCI: Using ACPI for IRQ routing
PCI: If a device does not work, try "pci=routeirq". If it helps, post a report
PCI: Cannot allocate resource region 7 of bridge 0000:00:1c.1
PCI: Cannot allocate resource region 8 of bridge 0000:00:1c.1
PCI: Cannot allocate resource region 9 of bridge 0000:00:1c.1

Rajesh Shah (the author of said commit) has since then acked that this small
change should probably be reverted:
> Looking at this closely now, checking for the result does appear
> to be wrong. Binding a driver for a device should be optional,
> and should not fail adding the device to the acpi list. I suspect
> a previous iteration through this code failed to find a driver
> match, returned failure to the caller and caused bad things to
> happen. So, your patch looks good to me.

The main diagnosis/discussion has been at:
https://bugzilla.novell.com/show_bug.cgi?id=116763

There are also some other reports elsewhere:
http://bugzilla.kernel.org/show_bug.cgi?id=5221
http://bugs.gentoo.org/112601

So far the investigation/fixing has been done by Thomas Renninger and others.
I'm just hoping to breathe some life into an issue which has been sitting
around for nearly 3 months.

If acceptable, please apply.


Attachments:
acpi-scan.patch (812.00 B)