Re: [PATCH 1/4] PCI: pciehp: Clean up debug logging

[Bjorn Helgaas]

[+cc Rafael]

On Thu, Jun 18, 2015 at 1:08 PM, Rajat Jain <rajatja@xxxxxxxxxx> wrote:
> On Thu, Jun 18, 2015 at 11:01 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
>> On Thu, Jun 18, 2015 at 12:27 PM, Rajat Jain <rajatja@xxxxxxxxxx> wrote:
>>> Hi,
>>>
>>> On Thu, Jun 18, 2015 at 9:12 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
>>>> The pciehp debug logging is overly verbose and often redundant.  Almost all
>>>> of the information printed by dbg_ctrl() is also printed by the normal PCI
>>>> core enumeration code and by pcie_init().
>>>>
>>>> Remove the redundant debug info.
>>>>
>>>> When claiming a pciehp bridge, we print the slot characteristics, e.g.,
>>>>
>>>>   Slot #6 AttnBtn- AttnInd- PwrInd- PwrCtrl- MRL- Interlock- NoCompl+ LLActRep+
>>>>
>>>> Add the Hot-Plug Capable and Hot-Plug Surprise bits to this information,
>>>
>>> If the slot is not hotplug capable. then pciehp wouldn't claim it in
>>> the first place.
>>>
>>> So printing of "hotplug capable" may really not be needed..
>>
>> Yes, I did think about that, and you're right that it probably isn't
>> needed.  But the criteria for claiming a slot and deciding whether
>> acpiphp or pciehp should manage it are not 100% clear yet, so I
>> figured it wouldn't hurt to be a bit more transparent.
>
> Sounds right.
>
> Reviewed-by : Rajat Jain <rajatja@xxxxxxxxxx>
>
> Side note: To clarify when and why the slot was claimed by pciehp or
> acpihp, do you think we need some mumbling / logging in
> acpi_pci_detect_ejectable() or pciehp_acpi_slot_detection_check()?

Maybe so (but I haven't added anything).

My intuition is that acpiphp and pciehp are not really symmetric.  I
think pciehp should claim PCIe downstream ports (Root Ports and
Downstream Ports) when _OSC has granted us control.

But it doesn't seem like acpiphp should decide whether to claim
certain devices based on whether they have _ADR, _EJ0, _RMV, etc.
Shouldn't it just be integrated with the ACPI core so  it can field
notifications from the platform, no matter what methods are present,
and even if pciehp has claimed a bridge in that scope?

Bjorn
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/