Re: [RFC PATCH v3 7/9] ipu3-cio2: Check if pci_dev->dev's fwnode is a software_node in cio2_parse_firmware() and set FWNODE_GRAPH_DEVICE_DISABLED if so

Dan Scally
2020-10-20T22:56:06Z

Hi Sakari

On 20/10/2020 23:49, Sakari Ailus wrote:
> Hi Dan,
>
> On Tue, Oct 20, 2020 at 08:56:07PM +0100, Dan Scally wrote:
>> Hi Sakari
>>
>> On 20/10/2020 13:06, Sakari Ailus wrote:
>>> Hi Andy,
>>>
>>> On Tue, Oct 20, 2020 at 12:19:58PM +0300, Andy Shevchenko wrote:
>>>> On Mon, Oct 19, 2020 at 11:59:01PM +0100, Daniel Scally wrote:
>>>>> fwnode_graph_get_endpoint_by_id() will optionally parse enabled devices
>>>>> only; that status being determined through the .device_is_available() op
>>>>> of the device's fwnode. As software_nodes don't have that operation and
>>>>> adding it is meaningless, we instead need to check if the device's fwnode
>>>>> is a software_node and if so pass the appropriate flag to disable that
>>>>> check
>>>> Period.
>>>>
>>>> I'm wondering if actually this can be hidden in fwnode_graph_get_endpoint_by_id().
>>> The device availability test is actually there for a reason. Some firmware
>>> implementations put all the potential devices in the tables and only one
>>> (of some) of them are available.
>>>
>>> Could this be implemented so that if the node is a software node, then get
>>> its parent and then see if that is available?
>>>
>>> I guess that could be implemented in software node ops. Any opinions?
>> Actually when considering the cio2 device, it seems that
>> set_secondary_fwnode() actually overwrites the _primary_, given
>> fwnode_is_primary(dev->fwnode) returns false. So in at least some cases,
>> this wouldn't work.
> Ouch. I wonder when this happens --- have you checked what's the primary
> there? I guess it might be if it's a PCI device without the corresponding
> ACPI device node?
Yes; it's null, and I think that diagnosis is correct.
> I remember you had an is_available implementation that just returned true
> for software nodes in an early version of the set? I think it would still
> be a lesser bad in this case.
Yep - I can put that back in and just drop this patch then; fine for me.