On Thursday 08 March 2007 11:57, Thomas Renninger wrote:
> On Tue, 2007-03-06 at 12:10 -0500, Dave Jones wrote:
> > On Tue, Mar 06, 2007 at 03:58:01PM +0800, Zhao Forrest wrote:
> > > On 3/6/07, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > > > On Tue, 6 Mar 2007 02:43:12 -0500 Dave Jones <davej@xxxxxxxxxx> wrote:
> > > >
> > > > > On Mon, Mar 05, 2007 at 11:30:37PM -0800, Andrew Morton wrote:
> > > > > >
> > > > > > I always get stuff like this coming out when I boot my x86_64 machine:
> > > > > >
> > > > > > asus_acpi: Unknown symbol backlight_device_unregister
> > > > > > asus_acpi: Unknown symbol backlight_device_register
> > > > > > ibm_acpi: Unknown symbol backlight_device_unregister
> > > > > > ibm_acpi: Unknown symbol backlight_device_register
> > > > > > toshiba_acpi: Unknown symbol backlight_device_unregister
> > > > > > toshiba_acpi: Unknown symbol backlight_device_register
> > > > > > video: Unknown symbol backlight_device_unregister
> > > > > > video: Unknown symbol backlight_device_register
> > > > > >
> > > > > > This is a nocoma server, not a laptop. I'm not sure how those modules are
> > > > > > even getting loaded. The distro is FC4, which might be doing something
> > > > > > peculiar.
> > > > >
> > > > > I covered this on the list last week. There's no way to
> > > > > have a module autoload based on dmi strings or the like,
> > > > > (Which is the only sane way these modules can determine
> > > > > if they need to run).
> > > > >
> > > > > Given the absense of mechanism, there's a pretty gross hack
> > > > > in Fedora's rc.sysinit which loads every module in drivers/acpi/*/*
> > > > > that it finds. Shameful I know.
> > > >
> > > > I thought it might be something like that. I'm a bit surprised that we
> > > > can't get at the DMI stuff from userspace, or export it from the kernel.
> > > > But whatever.
> > >
> > > I have a question: why can't we get at the DMI stuff from userspace
> > > since "dmidecode" is a tool in userspace?
> >
> > We can, but we could do better.
> > What's missing is an *event* that udev can see, so that it
> > knows what to do.
> >
> > Imagine: asus_acpi gets a MODULE_DMI("ASUS") or whatever, and then
> > at boottime, we register a sysfs modalias of the system DMI string.
> > Suddenly we have two pieces of the puzzle, and udev will see the
> > modalias and happily pull in any modules that match the alias.
> >
> > All without any changes to userspace at all.
>
> I also saw asus_acpi module loaded on a server.
> rmmodding it results in (sorry about escape chars):
>
>
> BUG: at lib/kref.c:32 kref_get()
>
> Call Trace:
> [<ffffffff80232ed2>] kref_get+0x2f/0x34
> [<ffffffff802501ed>] kobject_get+0x12/0x17
> [<ffffffff80386422>] get_driver+0x14/0x1a
> [<ffffffff80386439>] driver_remove_file+0x11/0x32
> [<ffffffff803858e8>] bus_remove_driver+0x1c/0x90
> [<ffffffff8038637e>] driver_unregister+0xd/0x16
> [<ffffffff8829e79d>] :asus_acpi:asus_acpi_exit+0x21/0x35
> Starting D-Bus d [<ffffffff802981ad>] sys_delete_module+0x1b1/0x1e0
> aemonESC7ESC[?25l^MESC[ [<ffffffff80220069>] dma_alloc_coherent
> +0x57/0x23f
> 80CESC[10DESC[1;32md [<ffffffff8025511e>] system_call+0x7e/0x83
> oneESC[m^OESC8ESC[?25h^M
>
> BUG: at lib/kref.c:32 kref_get()
>
> Call Trace:
> [<ffffffff80232ed2>] kref_get+0x2f/0x34
> [<ffffffff802501ed>] kobject_get+0x12/0x17
> Starting irqbala [<ffffffff80386422>] get_driver+0x14/0x1a
> nce ESC7ESC[?25l^MESC[8 [<ffffffff803115bb>] kobject_release+0x0/0x9
> 0CESC[10DESC[1;32mdo [<ffffffff80386439>] driver_remove_file+0x11/0x32
> neESC[m^OESC8ESC[?25h^M^M [<ffffffff803858f7>] bus_remove_driver
> +0x2b/0x90
>
> acpid: loading [<ffffffff8038637e>] driver_unregister+0xd/0x16
> ACPI modules ( a [<ffffffff8829e79d>] :asus_acpi:asus_acpi_exit
> +0x21/0x35
> c battery button [<ffffffff802981ad>] sys_delete_module+0x1b1/0x1e0
> ) ESC7ESC[?25l^MESC[80 [<ffffffff80220069>] dma_alloc_coherent
> +0x57/0x23f
> CESC[10DESC[1;32mdon [<ffffffff8025511e>] system_call+0x7e/0x83
> eESC[m^OESC8ESC[?25h^M
>
> acpid: will not Unable to handle kernel NULL pointer dereference at
> 0000000000000020 RIP:
> [<ffffffff803f8a02>] klist_del+0xa/0x46
> PGD 21f3d0067 PUD 21efa9067 PMD 0
> Oops: 0000 [1] SMP
> CPU 0
>
>
> This patch fixes it (Len, can you apply this?):
Applied.
thanks,
-Len
> Do not load asus_acpi if no device has been found
>
> Do not rely on acpi_bus_register_driver() return value which
> is always zero, even no device has been found.
>
> ---
> drivers/acpi/asus_acpi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-2.6.21-rc3/drivers/acpi/asus_acpi.c
> ===================================================================
> --- linux-2.6.21-rc3.orig/drivers/acpi/asus_acpi.c
> +++ linux-2.6.21-rc3/drivers/acpi/asus_acpi.c
> @@ -1398,7 +1398,7 @@ static int __init asus_acpi_init(void)
> if (!asus_hotk_found) {
> acpi_bus_unregister_driver(&asus_hotk_driver);
> remove_proc_entry(PROC_ASUS, acpi_root_dir);
> - return result;
> + return -ENODEV;
> }
>
> asus_backlight_device = backlight_device_register("asus",NULL,NULL,
>
>
> -
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