Re: [PATCH] firmware loader: inform direct failure when udev loader is disabled

["Luis R. Rodriguez" <mcgrof@suse.com>]

On Wed, Jul 02, 2014 at 09:51:36AM +0800, Ming Lei wrote:
> On Wed, Jul 2, 2014 at 9:01 AM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
> > On Tue, Jul 01, 2014 at 11:22:07AM +0200, Takashi Iwai wrote:
> >> At Tue, 1 Jul 2014 11:54:24 +0800,
> >> Ming Lei wrote:
> >> >
> >> > On Tue, Jul 1, 2014 at 7:30 AM, Luis R. Rodriguez
> >> > <mcgrof@do-not-panic.com> wrote:
> >> > > From: "Luis R. Rodriguez" <mcgrof@suse.com>
> >> > >
> >> > > Now that the udev firmware loader is optional request_firmware()
> >> > > will not provide any information on the kernel ring buffer if
> >> > > direct firmware loading failed and udev firmware loading is disabled.
> >> > > If no information is needed request_firmware_direct() should be used
> >> > > for optional firmware, at which point drivers can take on the onus
> >> > > over informing of any failures, if udev firmware loading is disabled
> >> > > though we should at the very least provide some sort of information
> >> > > as when the udev loader was enabled by default back in the days.
> >> > >
> >> > > With this change with a simple firmware load test module [0]:
> >> > >
> >> > > Example output without FW_LOADER_USER_HELPER_FALLBACK
> >> > >
> >> > > platform fake-dev.0: Direct firmware load for fake.bin failed with error -2
> >> > >
> >> > > Example without FW_LOADER_USER_HELPER_FALLBACK
> >> > >
> >> > > platform fake-dev.0: Direct firmware load for fake.bin failed with error -2
> >> > > platform fake-dev.0: Falling back to user helper
> >> > >
> >> > > Without this change without FW_LOADER_USER_HELPER_FALLBACK we get no output
> >> > > logged upon failure.
> >> > >
> >> > > [0] https://github.com/mcgrof/fake-firmware-test.git
> >> > >
> >> > > Cc: Tom Gundersen <teg@jklm.no>
> >> > > Cc: Ming Lei <ming.lei@canonical.com>
> >> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >> > > Cc: Abhay Salunke <Abhay_Salunke@dell.com>
> >> > > Cc: Stefan Roese <sr@denx.de>
> >> > > Cc: Arnd Bergmann <arnd@arndb.de>
> >> > > Cc: Kay Sievers <kay@vrfy.org>
> >> > > Cc: Takashi Iwai <tiwai@suse.de>
> >> > > Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
> >> > > ---
> >> > >
> >> > >  drivers/base/firmware_class.c | 12 ++++++++----
> >> > >  1 file changed, 8 insertions(+), 4 deletions(-)
> >> > >
> >> > > diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> >> > > index 46ea5f4..23274d8 100644
> >> > > --- a/drivers/base/firmware_class.c
> >> > > +++ b/drivers/base/firmware_class.c
> >> > > @@ -101,8 +101,10 @@ static inline long firmware_loading_timeout(void)
> >> > >  #define FW_OPT_NOWAIT  (1U << 1)
> >> > >  #ifdef CONFIG_FW_LOADER_USER_HELPER
> >> > >  #define FW_OPT_USERHELPER      (1U << 2)
> >> > > +#define FW_OPT_FAIL_WARN       0
> >> > >  #else
> >> > >  #define FW_OPT_USERHELPER      0
> >> > > +#define FW_OPT_FAIL_WARN       (1U << 3)
> >> > >  #endif
> >> > >  #ifdef CONFIG_FW_LOADER_USER_HELPER_FALLBACK
> >> > >  #define FW_OPT_FALLBACK                FW_OPT_USERHELPER
> >> > > @@ -1116,10 +1118,11 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
> >> > >
> >> > >         ret = fw_get_filesystem_firmware(device, fw->priv);
> >> > >         if (ret) {
> >> > > -               if (opt_flags & FW_OPT_USERHELPER) {
> >> > > +               if (opt_flags & (FW_OPT_FAIL_WARN | FW_OPT_USERHELPER))
> >> > >                         dev_warn(device,
> >> > > -                                "Direct firmware load failed with error %d\n",
> >> > > -                                ret);
> >> > > +                                "Direct firmware load for %s failed with error %d\n",
> >> > > +                                name, ret);
> >> >
> >> > Maybe the warning can be always printed out since
> >> > (FW_OPT_FAIL_WARN | FW_OPT_USERHELPER) should be
> >> > always true.
> >>
> >> Yes, it'd be simpler.  Let's reduce lines! :)
> >
> > Actually we don't want to warn when request_firmware_direct() is used right? That's really what
> 
> Yes, that is for the CPU microcode update in which it is common to
> fail in direct loading, and x86 guys hate the warning.

I've extended use of request_firmware_direct() to drivers that also load
non-firmware but optional config files, EEPROM override, etc.

> > I meant to upkeep while adding a warning when _direct() is not used. So how about
> > this as an ammendment:
> 
> Yes, the idea is right, and it is good to make request_firmware_direct()
> not depend on CONFIG_FW_LOADER_USER_HELPER, and with
> one FW_OPT_DIRECT_ONLY flag together it should work.

OK.

> > diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> > index 23274d8..4f6adf3 100644
> > --- a/drivers/base/firmware_class.c
> > +++ b/drivers/base/firmware_class.c
> > @@ -66,13 +68,12 @@ static inline void release_firmware(const struct firmware *fw)
> >  {
> >  }
> >
> > -#endif
> > +static inline int request_firmware_direct(const struct firmware **fw,
> > +                                         const char *name,
> > +                                         struct device *device)
> > +{
> > +       return -EINVAL;
> > +}
> 
> You define two request_firmware_direct?

This is the negative of

#if defined(CONFIG_FW_LOADER) || (defined(CONFIG_FW_LOADER_MODULE) && defined(MODULE))

We have two also for request_firmware().

Will send out a v2.

  Luis