On Tue, Sep 03, 2024 at 07:15:36PM +0200, Niklas Söderlund 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>
write is similarly broken, but i don't think we care about that.
Thanks
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Andrew
