Re: [PATCH 1/2] dm: improve logging for missing uclass

Le jeu. 6 août 2026 à 19:01, Simon Glass <[email protected]> a écrit :
>
> Hi Julien,
>
> On 2026-08-06T13:05:19, Julien Stephan <[email protected]> wrote:
> > dm: improve logging for missing uclass
> >
> > When a uclass definition is missing for an enabled driver, the board
> > cannot boot, and without any extra debug option enabled the following
> > error is displayed:
> >
> >   initcall_run_r(): initcall initr_dm() failed ### ERROR ### Please
> >   RESET the board ###
> >
> > There is a debug message using dm_warn(), which is not displayed by
> > default.  Since this is a fatal error preventing the board from booting,
> > the log level should be at least ERROR.
> >
> > Signed-off-by: Julien Stephan <[email protected]>
> >
> > drivers/core/uclass.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
>
> > diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
> > @@ -60,8 +60,9 @@ static int uclass_add(enum uclass_id id, struct uclass **ucp)
> >       *ucp = NULL;
> >       uc_drv = lists_uclass_lookup(id);
> >       if (!uc_drv) {
> > -             dm_warn("Cannot find uclass for id %d: please add the UCLASS_DRIVER() declaration for this UCLASS_... id\n",
> > -                     id);
> > +             log(LOGC_DM, LOGL_ERR,
> > +                 "Cannot find uclass for id %d: please add the UCLASS_DRIVER() declaration for this UCLASS_... id\n",
> > +                 id);
>
> This file sets LOG_CATEGORY to LOGC_DM at the top, so log_err() would
> be cleaner:
>
>     log_err("Cannot find uclass for id %d: please add the
> UCLASS_DRIVER() declaration for this UCLASS_... id\n",
>             id);
>
> The idea with this was that by returning -EPFNOSUPPORT (unused
> elsewhere in U-Boot (he says...)) it would indicate this problem,
> without bloating the code with a large message. This code is used in
> SPL where code size is at a premium. I don't see the error number
> though, which I added here:
>
> 13123276806 initcall: Adjust the failure message and return value
>
> Hmm yes it was dropped in the initcall move back to the header file.
>
> We already have DM_WARN to help people with debugging, so perhaps
> instead we should just enable that by default in U-Boot proper?
>

Hi Simon,

I didn't think about the impact on SPL. I understand your point, but I
do feel a fatal error deserves a proper message.

So what about reducing this long message to something shorter, using
log_err() as you suggested:

log_err("uclass %d: no UCLASS_DRIVER()\n", id);

That keeps a readable, greppable hint while cutting most of the SPL
size overhead.

I didn't audit all the dm_warn() callers, but enabling DM_WARN by
default feels overkill. I suspect several of them are
genuinely non-fatal warnings.

Otherwise, we could just drop this patch, since patch 2 now prints the
-EPFNOSUPPORT value on failure.

What do you think?

Cheers,
Julien

> Regards,
> Simon