[syslinux] syslinux (pxelinux.0) debug prints

[Spike White]

>Message: 6
>Date: Fri, 30 May 2014 07:35:30 -0400
>From: Gene Cumm <gene.cumm at gmail.com>
>To: Wissam Shoukair <wissams at mellanox.com>
>Cc: For discussion of Syslinux and tftp-hpa <syslinux at zytor.com>
>Subject: Re: [syslinux] syslinux (pxelinux.0) debug prints
>Message-ID:
>        <CAD0Rxem_P4kOycVcSZUuaTjdKe=Gm5MLTjO6P6dMkbtsLOrVNQ at mail.gmail.com
>
>Content-Type: text/plain; charset=UTF-8
>
>On Thu, May 29, 2014 at 12:50 PM, Wissam Shoukair <wissams at mellanox.com>
>wrote:
>> Op 2014-05-29 om 06:27 schreef Gene Cumm:
>>> On May 29, 2014 5:25 AM, "Wissam Shoukair" <wissams at mellanox.com> wrote:
>>> >
>>> > Hi Gene,
>>> >
>>> > I was wondering how I can set the ???printf??? output to be visible on
>the
>>> screen? (I???m using syslinux-6.03-pre02)
>>>
>>> printf () or dprintf ()? You need to watch what functions are available
>at
>>> the time you want to print. For example, printf isn't available until
>>> ldlinux.c32 is loaded.
>>>
>>> Why not 6.03-pre12?
>>>
>>
>> I have to work with this version???
>
>> Do you have any suggestions?
>
>On Thu, May 29, 2014 at 1:15 PM, H. Peter Anvin <hpa at zytor.com> wrote:
>> On 05/29/2014 09:50 AM, Wissam Shoukair wrote:
>>>
>>> I have to work with this version???
>>>
>>
>> That is highly unfortunate, since the version you "have to work with"
>> has a number of bugs, many of which have already been fixed.
>>
>> -hpa
>
>I agree.
>
>The biggest suggestion is to NOT use a pre-release version which has
>numerous bugs resolved in later pre-release versions as you are likely to
>encounter at least one of them. I believe at least some of these bugs were
>carry-overs from 5.0x.
>
>--
>-Gene
>

I totally second Gene's recommendation;  I banged my head against the wall
for several
days using 6.03-pre3.  There were tftp client bugs there.

On Gene's advise, I tried 6.03-pre6.  And it just worked!!

In the interest of completeness.....

For debugging printf's in pxelinux.0, I believe what you're looking for is
the gnu-efi lib's
APrint() function.

As the routine's description states:

    For those whom really can't deal with unicode, a print
    function that takes an ascii format string

That allowed me to create debugging printfs that appeared on the pxelinux.0
boot console.

But if you use a recent pre-release, you won't have to use debugging
printfs.

Spike