Re: [PATCH] PCI: tegra: Fix building Tegra194 PCIe driver

[Jon Hunter <jonathanh@nvidia.com>]

Hi Krzysztof,

On 19/05/2021 17:57, Krzysztof Wilczyński wrote:
> Hi Jon,
> 
>> Commit 7f100744749e ("PCI: tegra: Add Tegra194 MCFG quirks for ECAM
>> errata") caused a couple build regressions for the Tegra194 PCIe driver
>> which are:
>>
>> 1. The Tegra194 PCIe driver can no longer be built as a module. This
>>    was caused by removing the Makefile entry to build the pcie-tegra.c
>>    based upon the CONFIG_PCIE_TEGRA194 option. Therefore, restore this
>>    so that we can build the driver as a module if ACPI support is not
>>    enabled in the kernel.
>> 2. If CONFIG_PCIE_TEGRA194 is configured to build the driver as a
>>    module, at the same time that CONFIG_ACPI and CONFIG_PCI_QUIRKS are
>>    selected to build the driver into the kernel, then the necessary
>>    functions in the driver to probe and remove the device when booting
>>    with device-tree and not compiled into to the driver. This prevents
>>    the PCIe devices being probed when booting with device-tree. Fix this
>>    by using the IS_ENABLED() macro.
> 
> Thank you for fixing this!  Much appreciated.
> 
> There are also few build time warnings related to these changes you
> mention above, as per:
> 
>   drivers/pci/controller/dwc/pcie-tegra194.c:259:18: warning: ‘event_cntr_data_offset’ defined but not used [-Wunused-const-variable=]
>   drivers/pci/controller/dwc/pcie-tegra194.c:250:18: warning: ‘event_cntr_ctrl_offset’ defined but not used [-Wunused-const-variable=]
>   drivers/pci/controller/dwc/pcie-tegra194.c:243:27: warning: ‘pcie_gen_freq’ defined but not used [-Wunused-const-variable=]
> 
> We could bill two birds with one stone, so to speak, and move these
> variables into the block behind the CONFIG_PCIE_TEGRA194 and
> CONFIG_PCIEASPM guards respectively, so that these symbols are no longer
> unused.

Ah good to know. Yes I can incorporate into this change as well. Thanks
for letting me know.

> Also, since this change fixes and issue introduced in a different
> commit, then it would be prudent to add the "Fixes:" tag.

Yes it would. I had missed that, but will add.

Thanks!
Jon

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