[U-Boot] [PATCH 02/10] USB add macros for debugging usb device setup.

Mike Frysinger vapier at gentoo.org
Sun Nov 1 15:09:49 CET 2009


On Sunday 01 November 2009 09:02:22 Tom wrote:
> Mike Frysinger wrote:
> > On Saturday 31 October 2009 22:00:09 Tom wrote:
> >> Mike Frysinger wrote:
> >>> On Saturday 31 October 2009 13:37:39 Tom Rix wrote:
> >>>> +#ifdef DEBUG
> >>>> +static inline void print_device_descriptor(struct
> >>>> usb_device_descriptor *d) +{
> >>>> +	serial_printf("usb device descriptor \n");
> >>>
> >>> do you really need serial_printf() ?  what's wrong with debug() ?  then
> >>> you dont even really need "#ifdef DEBUG" around all the functions ...
> >>
> >> The explicit serial_printf is done because this patch set changes the
> >> stdin and stdout for serial to usbtty.
> >>
> >> When you use printf to debug printf, you regress into a bad state.
> >
> > so in your specific use case it makes sense *some* of the time (usbtty is
> > enabled and the console has been changed to it), but in the general use
> > case (usb debugging), it does not.  why not make it intelligent instead
> > of penalizing everyone to use their serial console:
> >  - default to debug()
> >  - if usbtty support is enabled, check the current stdout console to see
> > if it's set to a usbtty, and only then fall back to forcing
> > serial_printf()
> 
> A better solution would be to combine this logic into debug().

yes and no.  debug() should not change, but a new debug function would 
probably make sense.  debug_stdio() where the first argument would be the 
device name you're debugging ("usbtty" here) and would handle sending directly 
to the serial functions if current stdio is set to that.

i look forward to your proposed code ;)
-mike
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