[syslinux] boot... round 2

[poma]

On 30.06.2015 22:52, Gene Cumm wrote:
> On Tue, Jun 30, 2015 at 4:29 PM, poma <pomidorabelisima at gmail.com> wrote:
> 
>> "A real serial port that can reliably operate at 115200 8n1 may be
>> necessary."
>>
>> Gene, is there something special in "A real serial port" usage, compared to emulated?
> 
> I should restate: A serial port that responds on BIOS IO port 3F8h
> that can reliably operate at 115200 8n1 may be necessary.  A USB
> serial port that the BIOS doesn't bother setting up for IO port 3F8h
> is just random hardware.
> 
> In order to utilize it, the serial port should not be utilized for
> normal use (mixing gets ugly) and a special build must be made by
> changing mk/devel.mk (although it's been a while).  Lines 3 and 4 must
> be uncommented and line 5 must be commented out.  Booting such a build
> may take a long time while data is pumped over the serial.
> 

GCCWARN += -DDEBUG_MALLOC
GCCWARN += -DDEBUG_PORT=0x3f8 -DCORE_DEBUG=1

These directives have made it unnecessary:
- switch to 'isolinux-debug.bin' usage
- engage "serial 0" within the 'isolinux.cfg'

To put it another way, the effect is the same.


> Although perhaps not helpful in this case, I'd normally suggest a
> simpler config like the following:
> 
> 
> #syslinux.cfg-begin
> DEFAULT linux
> PROMPT 1
> 
> LABEL linux
>   LINUX vmlinuz
>   APPEND initrd=myinitrd.cgz my-options
> #syslinux.cfg-end
> 
> 
> The sole use such a simpler config could serve in this instance is to
> minimize the serial-debug data generated by a working build to compare
> against a broken build.
>