On Tue, Sep 3, 2024 at 7:16 PM Niklas Söderlund
<niklas.soderlund+renesas@xxxxxxxxxxxx> wrote:
> When reading registers from the PHY using the SIOCGMIIREG IOCTL any
> errors returned from either mdiobus_read() or mdiobus_c45_read() are
> ignored, and parts of the returned error is passed as the register value
> back to user-space.
>
> For example, if mdiobus_c45_read() is used with a bus that do not
> implement the read_c45() callback -EOPNOTSUPP is returned. This is
> however directly stored in mii_data->val_out and returned as the
> registers content. As val_out is a u16 the error code is truncated and
> returned as a plausible register value.
>
> Fix this by first checking the return value for errors before returning
> it as the register content.
>
> Before this patch,
>
> # phytool read eth0/0:1/0
> 0xffa1
>
> After this change,
>
> $ phytool read eth0/0:1/0
> error: phy_read (-95)
>
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
