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

[Wolfgang Denk]

Hello Simon,

ping...

In message <20200122121253.7B0B3240638 at gemini.denx.de> I wrote:
> 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

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
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