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

["Dall, Betty" <betty.dall@hpe.com>]

On 04/26/2016 02:33 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@hpe.com>
> 
> The patch itself looks OK to me, but why exactly do we need that thing in sysfs?
> 
> Thanks,
> Rafael
> 
Hi Rafael,

I am working on a platform where non-PCI hardware is changing quickly
and users want to check what hardware version they are running on. For
example, someone checks out a lab system and wants to see if the device
is the latest version or if it needs to be updated - they could cat the
sysfs hrv file to find the version. It is most useful for non-PCI
devices because lspci can list the hardware version for PCI devices; PCI
devices in my testing don't supply _HRV. But, there is not an easy
solution for non-PCI devices to get the hardware revision from user
space with out this hrv sysfs patch.

Originally, I added the sysfs hrv to my specific device driver. On
review, I thought it would a good improvement for all devices that have
an _HRV.

Thanks,
Betty