Re: [PATCH] PCI: endpoint: pci-epf-test: Roll back BAR mapping when subrange setup fails

[Niklas Cassel <cassel@kernel.org>]

On Tue, Mar 17, 2026 at 11:29:41AM +0100, Christian Bruel wrote:
> 
> 
> On 3/17/26 11:12, Niklas Cassel wrote:
> > On Tue, Mar 17, 2026 at 11:01:28AM +0100, Christian Bruel wrote:
> > > 
> > > 
> > > > 
> > > > So we will need to add a SKIP ENOSPC case in TEST_F(pci_ep_bar,
> > > > BAR_SUBRANGE_TEST)
> > > > 
> > > Re-checking this, no need for ENOSPC test. The real condition would be
> > > EBUSY. Which can be handled nicely in a stm32 ep_map_addr helper.
> > 
> > Are you sure that it returns EBUSY and not ENOSPC?
> > 
> > I would have expected the error to be ENOSPC when there are no free inbound
> > window:
> > https://github.com/torvalds/linux/blob/v7.0-rc4/drivers/pci/controller/dwc/pcie-designware-ep.c#L307-L312
> 
> dw_pcie_ep_ib_atu_addr() returns ENOSPC. I was thinking to overload .set_bar
> with a stm32 helper to return EBUSY if the subrange bar is already reserved.
> 
> So whatever is best
>  - modify TEST_F to SKIP if ENOSPC
> or
>  - Add a specific platform .set_bar helper to return EBUSY, already handled
> in the test.

I think "modify TEST_F to SKIP if ENOSPC",
since it will solve the problem for all platforms that have few inbound iATUs.


Kind regards,
Niklas