[U-Boot] [PATCH 1/4] dm: device_remove: Don't return in device_chld_remove() upon error

[Simon Glass]

Hi Stefan,

On 6 April 2017 at 07:29, Stefan Roese <sr at denx.de> wrote:
> On my x86 platform I've noticed, that calling dm_uninit() or the new
> function dm_remove_devices_flags() does not remove the desired device at
> all. Debugging showed, that the serial uclass returns -EPERM in
> serial_pre_remove() and this leads to a complete stop of the device
> removal pretty early, as the serial device is one of the first ones in
> the DM. Here the dm tree output:
>
> => dm tree
>  Class       Probed   Name
> ----------------------------------------
>  root        [ + ]    root_driver
>  rsa_mod_exp [   ]    |-- mod_exp_sw
>  serial      [ + ]    |-- serial
>  rtc         [   ]    |-- rtc
>  timer       [ + ]    |-- tsc-timer
>  syscon      [ + ]    |-- pch_pinctrl
>  ...
>
> In this example, device_remove(root) will stop directly after trying to
> remove the "serial" device.
>
> To solve this problem, this patch removes the return upon error check in
> the device_remove() call in device_chld_remove(). This leads to
> device_chld_remove() continuing with the device_remove() call to the
> following child devices.

I think the right solution is to find out why stdio_deregister_dev()
fails. It is probably because the device is in use within the stdio
variables. Perhaps you need to remove it first?

>
> Signed-off-by: Stefan Roese <sr at denx.de>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Bin Meng <bmeng.cn at gmail.com>
> ---
>  drivers/core/device-remove.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/core/device-remove.c b/drivers/core/device-remove.c
> index cc0043b990..8b46f3343e 100644
> --- a/drivers/core/device-remove.c
> +++ b/drivers/core/device-remove.c
> @@ -52,15 +52,11 @@ static int device_chld_unbind(struct udevice *dev)
>  static int device_chld_remove(struct udevice *dev, uint flags)
>  {
>         struct udevice *pos, *n;
> -       int ret;
>
>         assert(dev);
>
> -       list_for_each_entry_safe(pos, n, &dev->child_head, sibling_node) {
> -               ret = device_remove(pos, flags);
> -               if (ret)
> -                       return ret;
> -       }
> +       list_for_each_entry_safe(pos, n, &dev->child_head, sibling_node)
> +               device_remove(pos, flags);

I think we should keep the error checking here.

>
>         return 0;
>  }
> --
> 2.12.2
>

Regards,
Simon