Re: [PATCH] PCI: rockchip-host: Enable async probe by default

[Igor Velkov <iav@iav.lv>]

On Mon, Nov 09, 2026 at 02:22:02PM -0600, Bjorn Helgaas wrote:
> I don't know what the SD card has to do with PCIe.  Seems like there's
> some SD issue, and making PCIe async happens to avoid it?  Sounds
> fragile to me.
>
> Other changes like c0e1eb441b1d justify it by allowing other drivers
> to load in parallel to reduce boot time, which is a good reason.  But
> apparently here it makes a functional difference as well, which feels
> sketchy.  E.g., what other drivers need to use async probe to avoid
> similar issues?

You're right that the real problem is ordering: nothing makes dw_mmc wait
for the RK3399 io-domain driver, which sets the 1.8 V level of the SD
pins. [1] tried to add that dependency and was not merged. Async probe
only stops this driver from holding the deferred-probe worker for ~0.7 s;
any other slow probe in that window breaks UHS the same way.

Is there a way to express this dependency that you would accept?

[1] https://lore.kernel.org/all/20230904115816.1237684-1-s.hauer@pengutronix.de/

--
Igor Velkov