Re: [RFC] [PATCH] ACPI :Remove the EC space handler explicitly when failing in _REG object

[Alexey Starikovskiy <aystarik@gmail.com>]

This is hardly a "fix", you just disable EC on this machine... Famous 
question
"how windows runs on this machine?" is not answered...

Regards,
Alex.

Zhao Yakui wrote:
> Hi, All
>
>     On some laptops as it fails in evaluating the _REG object, which brings that
> EC device can't be initialized correctly. But the EC space handler is not removed.
> In such case maybe EC internal register will still be accessed in AML code. It is
> not reasonable.
>     The following patch is to fix the above issue. When it fails in evaluating the
> _REG object, the EC space handler should be removed explicitly. 
>     Thanks for the comments.
>     
>
>     On some laptops the incorrect status is returned by acpi_install_space
> _handler because of the buggy _REG object, which causes that the EC device can't
> be initialized correctly. 
>     In such case it will be appropriate that the EC space handler is removed
> explicitly if OS fails in evaluating _REG object.
>
> http://bugzilla.kernel.org/show_bug.cgi?id=11884
>
> Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
> cc:Alexey Starikovskiy <astarikovskiy@suse.de>
> ---
>  drivers/acpi/ec.c |   11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> Index: linux-2.6/drivers/acpi/ec.c
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/ec.c
> +++ linux-2.6/drivers/acpi/ec.c
> @@ -916,6 +916,17 @@ static int ec_install_handlers(struct ac
>  			printk(KERN_ERR "Fail in evaluating the _REG object"
>  				" of EC device. Broken bios is suspected.\n");
>  		} else {
> +			/*
> +			 * If incorrect status is returned because of the buggy
> +			 * _REG object, the EC space handler should be
> +			 * uninstalled explicitly.
> +			 * Otherwise maybe the EC internal register is still
> +			 * accessed in AML code although EC device is not
> +			 * initialized correctly.
> +			 */
> +			acpi_remove_address_space_handler(ec->handle,
> +						ACPI_ADR_SPACE_EC,
> +						&acpi_ec_space_handler);
>  			acpi_remove_gpe_handler(NULL, ec->gpe,
>  				&acpi_ec_gpe_handler);
>  			return -ENODEV;
>
>
> --
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