Re: [PATCH v3] driver core: Don't probe devices after bus_type.match() probe deferral

[Linus Walleij]

> Both __device_attach_driver() and __driver_attach() check the return
> code of the bus_type.match() function to see if the device needs to be
> added to the deferred probe list. After adding the device to the list,
> the logic attempts to bind the device to the driver anyway, as if the
> device had matched with the driver, which is not correct.
>
> If __device_attach_driver() detects that the device in question is not
> ready to match with a driver on the bus, then it doesn't make sense for
> the device to attempt to bind with the current driver or continue
> attempting to match with any of the other drivers on the bus. So, update
> the logic in __device_attach_driver() to reflect this.
>
> If __driver_attach() detects that a driver tried to match with a device
> that is not ready to match yet, then the driver should not attempt to bind
> with the device. However, the driver can still attempt to match and bind
> with other devices on the bus, as drivers can be bound to multiple
> devices. So, update the logic in __driver_attach() to reflect this.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Saravana Kannan <saravanak@xxxxxxxxxx>
> Fixes: 656b8035b0ee ("ARM: 8524/1: driver cohandle -EPROBE_DEFER from bus_type.match()")
> Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Signed-off-by: Isaac J. Manjarres <isaacmanjarres@xxxxxxxxxx>
> Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Reviewed-by: Saravana Kannan <saravanak@xxxxxxxxxx>

This fixes a QEMU regression for me:
Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij