[PATCH] [FS] Print error message for unknown device type

[Wolfgang Denk]

Dear Heiko,

In message <3546d28c-f638-5357-a20f-5d03db762be0 at denx.de> you wrote:
>
> > File system commands like "ls" etc. require a device type parameter.
> > If an unknown type is specified, they return an error code but no
> > visible feedback to the user:
> > 
> >   -> ls FOOBAR 1:1 /
> >   ->
> > 
> > Add an error message to make clear what happens, and why.
> > 
> > Signed-off-by: Wolfgang Denk <wd at denx.de>
> > ---
> >   disk/part.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
>
> Tested on wandboard.
>
> Tested-by: Heiko Schocher <hs at denx.de>

Thanks for testing.

> > -	if (dev < 0)
> > +	if (dev < 0) {
> > +		printf("** Unknown device type %s **\n", ifname);
> >   		goto cleanup;
> > +	}
>
> It would be nice to have here a list of supported devices, so a user
> can see what are valid arguments for ifname.

Yes, you are absolutely right.  I aready thought about this, but I
have to admit that I got stuck in the code; there are several
complexities - code for example for blk_driver_lookup_typename()
is duplicated both in drivers/block/blk_legacy.c   and in
drivers/block/blk-uclass.c;  I was not able to find any exported
interface that actually allows to get a list of supported device
drivers, and the things I tried all looked really ugly to me.

Adding Simon to Cc: - he has designed and written all this code and
should know better.

Simon, what would be a clean and elegant approach to get such a list
of supported drivers ?


In any case I recommend to accept this patch as is; this other thing
is additional information that can /should get added later in a
spearate patch.

Best regards,

Wolfgang Denk

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