On Wed, Sep 17, 2014 at 11:47:23PM +0200, Frans Klaver wrote:
> The disp attribute is write-only, but sysfs doesn't know this. Currently
> show_sys_acpi() is mimicking sysfs behavior, if the underlying acpi call
> should fail. This was introduced in 6dff29b63a5bf2eaf3 "eeepc-laptop:
> disp attribute should be write-only". This is not ideal; behaving like
> sysfs is better left to sysfs.
>
> Introduce EEEPC_CREATE_DEVICE_ATTR_WO() to instantiate a write-only
> attribute, and declare the disp attribute with it. Sysfs makes sure
> userspace can only write to disp at all times. This removes the need for
> mimicking the sysfs behavior in show_sys_acpi() and store_sys_acpi(),
> but we'll stick with -EIO, as changing sysfs return values should not be
> taken lightly.
>
> This change also causes EEEPC_CREATE_DEVICE_ATTR() to be used only for
> R/W attributes. This enables us to drop the _mode argument from the
> macro and use DEVICE_ATTR_RW() internally while we're at it. Append _RW
> to the name for readability.
>
> Signed-off-by: Frans Klaver <fransklaver@xxxxxxxxx>
> ---
> Here we're sticking with -EIO as return values. It should be said that the
> commit mentioned above did change the error value from -ENODEV to -EIO. I'm
> still in two minds about whether the show_sys_acpi and store_sys_acpi should go
> back to returning ENODEV. We'll probably stick with -EIO, though, as there is
> no strong reason other than "it was like that before".
>
> drivers/platform/x86/eeepc-laptop.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/platform/x86/eeepc-laptop.c b/drivers/platform/x86/eeepc-laptop.c
> index c6d765f..a85da4f 100644
> --- a/drivers/platform/x86/eeepc-laptop.c
> +++ b/drivers/platform/x86/eeepc-laptop.c
> @@ -311,14 +311,18 @@ static ssize_t show_sys_acpi(struct device *dev, int cm, char *buf)
> return store_sys_acpi(dev, _cm, buf, count); \
> }
>
> -#define EEEPC_CREATE_DEVICE_ATTR(_name, _mode, _cm) \
> +#define EEEPC_CREATE_DEVICE_ATTR_RW(_name, _cm) \
> EEEPC_ACPI_SHOW_FUNC(_name, _cm) \
> EEEPC_ACPI_STORE_FUNC(_name, _cm) \
> - static DEVICE_ATTR(_name, _mode, _name##_show, _name##_store)
> + static DEVICE_ATTR_RW(_name)
>
> -EEEPC_CREATE_DEVICE_ATTR(camera, 0644, CM_ASL_CAMERA);
> -EEEPC_CREATE_DEVICE_ATTR(cardr, 0644, CM_ASL_CARDREADER);
> -EEEPC_CREATE_DEVICE_ATTR(disp, 0200, CM_ASL_DISPLAYSWITCH);
> +#define EEEPC_CREATE_DEVICE_ATTR_WO(_name, _cm) \
> + EEEPC_ACPI_STORE_FUNC(_name, _cm) \
> + static DEVICE_ATTR_WO(_name)
> +
> +EEEPC_CREATE_DEVICE_ATTR_RW(camera, CM_ASL_CAMERA);
> +EEEPC_CREATE_DEVICE_ATTR_RW(cardr, CM_ASL_CARDREADER);
> +EEEPC_CREATE_DEVICE_ATTR_WO(disp, CM_ASL_DISPLAYSWITCH);
>
> struct eeepc_cpufv {
> int num;
Ah, you did what I asked on a previous patch here, nevermind :)
greg k-h
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