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

Tom Tom.Rix at windriver.com
Sun Nov 1 15:29:51 CET 2009


Mike Frysinger wrote:
> 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 ;)

This patch is not critical to the patchset.
It would be easier for me to remove it.

Tom




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