Re: [PATCH] I2C: Make I2C core able to be module when I2C_ACPI is selected.

From: Lan Tianyu
Date: Tue Aug 12 2014 - 22:53:22 EST

On 2014å08æ13æ 10:03, Wolfram Sang wrote:
> On Tue, Aug 12, 2014 at 12:53:21PM +0300, Mika Westerberg wrote:
>> On Mon, Aug 11, 2014 at 03:00:55PM +0800, Lan Tianyu wrote:
>>> Commit da3c6647(I2C/ACPI: Clean up I2C ACPI code and Add CONFIG_I2C_ACPI
>>> config) adds a new kernel config I2C_ACPI and make I2C core built in
>>> when the config is selected. This is wrong because distributions
>>> etc generally compile I2C as a module and the commit broken that.
>>> This patch is to make I2C core able to be a module when I2C_ACPI is
>>> selected. Original issue the commit da3c6647 tried to avoid will
>>> be fixed in ACPICA and it's rarely triggered during unloading module.
>>> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
>> I wonder if we can do
>> depends on I2C=y
>> here? If I understand it right, then we only build the ACPI_I2C if I2C
>> is compiled into the kernel. That way the problem da3c6647 tried to
>> solve doens't re-appear.
>> We can later on relax this once ACPICA has been fixed. Thoughts?
> I had the same idea yet my travel to Chicago interrupted thinking about
> it further. Once I get rid of my jetlag, I'll have a closer look. Unless
> you already came up with the perfect solution until then, of course ;)

Hi Mika & Wolfram:
I have one concern about "depends on I2C=y". If distribution config
file selects I2C core as a module, the original code can enumerate I2C
slave devices from ACPI table. But now I2C_ACPI depends on I2C core
built in, the I2C module can't enumerate devices from ACPI table. This
maybe a regression for distribution?

Best regards
Tianyu Lan
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at