Re: [PATCH] misc: pci_endpoint_test: Defer IRQ allocation until ioctl(PCITEST_SET_IRQTYPE)

[Niklas Cassel <cassel@kernel.org>]

On Wed, Apr 02, 2025 at 10:57:00AM +0200, Niklas Cassel wrote:
> Commit a402006d48a9 ("misc: pci_endpoint_test: Remove global 'irq_type'
> and 'no_msi'") changed so that the default IRQ vector requested by
> pci_endpoint_test_probe() was no longer the module param 'irq_type',
> but instead test->irq_type. test->irq_type is by default
> IRQ_TYPE_UNDEFINED (until someone calls ioctl(PCITEST_SET_IRQTYPE)).
> 
> However, the commit also changed so that after initializing test->irq_type
> to IRQ_TYPE_UNDEFINED, it also overrides it with driver_data->irq_type, if
> the PCI device and vendor ID provides driver_data.
> 
> This causes a regression for PCI device and vendor IDs that do not provide
> driver_data, and the driver now fails to probe on such platforms.
> 
> Considering that the pci endpoint selftests and the old pcitest always
> call ioctl(PCITEST_SET_IRQTYPE) before performing any test that requires
> IRQs, simply remove the allocation of IRQs in pci_endpoint_test_probe(),
> and defer it until ioctl(PCITEST_SET_IRQTYPE) has been called.
> 
> A positive side effect of this is that even if the endpoint controller has
> issues with IRQs, the user can do still do all the tests/ioctls() that do
> not require working IRQs, e.g. PCITEST_BAR and PCITEST_BARS.
> 
> This also means that we can remove the now unused irq_type from
> driver_data. The irq_type will always be the one configured by the user
> using ioctl(PCITEST_SET_IRQTYPE). (A user that does not know, or care
> which irq_type that is used, can use PCITEST_IRQ_TYPE_AUTO. This has
> superseded the need for a default irq_type in driver_data.)
> 
> Fixes: a402006d48a9c ("misc: pci_endpoint_test: Remove global 'irq_type' and 'no_msi'")
> Signed-off-by: Niklas Cassel <cassel@kernel.org>

Considering that e.g. NXP platforms are currently broken without this,
this should go into v6.15 IMHO.


Kind regards,
Niklas