Re: [PATCH] ACPI/device_sysfs: Add sysfs support for _HRV hardware revision

[Dall, Betty]

On 04/26/2016 02:39 PM, Rafael J. Wysocki wrote:
> On Wednesday, April 13, 2016 08:48:14 AM Betty Dall wrote:
>> The ACPI _HRV object on the device is used to supply Linux with
>> the device's hardware revision. This is an optional object. Add
>> sysfs support for the _HRV object if it exists on the device.
>>
>> Signed-off-by: Betty Dall <betty.dall@xxxxxxx>
>> ---
>>  drivers/acpi/device_sysfs.c | 24 ++++++++++++++++++++++++
>>  1 file changed, 24 insertions(+)
>>
>> diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
>> index b9afb47..bf12dbe 100644
>> --- a/drivers/acpi/device_sysfs.c
>> +++ b/drivers/acpi/device_sysfs.c
>> @@ -473,6 +473,21 @@ acpi_device_sun_show(struct device *dev, struct device_attribute *attr,
>>  }
>>  static DEVICE_ATTR(sun, 0444, acpi_device_sun_show, NULL);
>>  
>> +static ssize_t
>> +acpi_device_hrv_show(struct device *dev, struct device_attribute *attr,
>> +		     char *buf) {
>> +	struct acpi_device *acpi_dev = to_acpi_device(dev);
>> +	acpi_status status;
>> +	unsigned long long hrv;
>> +
>> +	status = acpi_evaluate_integer(acpi_dev->handle, "_HRV", NULL, &hrv);
>> +	if (ACPI_FAILURE(status))
>> +		return -ENODEV;
> 
> Actually, this should be -EIO I think.
> 
> Thanks,
> Rafael

Hi Rafael,

I picked -ENODEV because the _SUN and _STA show functions use -ENODEV
for a return value when the acpi_evaluate_integer() fails.

I checked in the sysfs code what the return value is used for and any
negative value is treated the same, that is, the sysfs code is not
looking specifically for -EIO.

Do you still want me to change it to -EIO?

-Betty