[U-Boot] Please pull u-boot-mpc85xx.git

Wolfgang Denk wd at denx.de
Mon Aug 2 23:06:31 CEST 2010


Dear Timur Tabi,

In message <4C57316B.7010706 at freescale.com> you wrote:
> 
> >> Audio is broken in Linux without this patch.  It's something I neglected to
> >> incorporate when in my initial P1022DS patch.
> > 
> > Well, this is U-Boot, not Linux.
> 
> I supposed it depends on your definition of a "bug".  If it's not doing
> something that it's supposed to be doing, and something else is broken
> because of it, is that a bug?
> 
> Without this patch, audio support on the P1022DS is completely broken.

We don't have audio support in U-Boot, do we?

> >> Perhaps "enable" is the wrong word, since the Linux audio driver doesn't
> >> detect the problem and just fails if U-Boot hasn't set up the signal routing
> >> correctly.
> > 
> > Sounds as if this should be fixed in Linux (too) ?
> 
> This has to do with enabling clock signals and pin muxing, something which
> is (IMHO) handled better in U-Boot than in Linux.

Once there was a good old tradition that a driver in an OS makes sure
to initialize the hardware as it needs it for reliable operation. I
think I remember to have seen this requested for Linux drivers not so
long ago.

To me it makes NO sense to enable clock signals for features that may
not be used at all - it will just increase the power dissipation of
the device without need nor benefit.  Only if the audio driver in
Linux actually gets initialized it should enable the required clock
signals (and disable them upon unloading).

But that's actually off topic here.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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