Syslinux - Jul 2013 - Dynamic debugging how to WAS: Syslinux-6.02-pre2 - booting 32-bit kernels from efi64

On Wed, 10 Jul, at 03:44:57PM, Andreas Heinlein wrote:
> Am 08.07.2013 18:32, schrieb Matt Fleming:
> >I just released 6.02-pre2 which includes support for booting 32-bit
> >kernels from efi64. I know a number of people wanted this feature, so
> >hopefully it will be tested in various environments.
> >
> >One thing to note is that it is not possible to boot a 32-bit kernel
> >from efi64 via the EFI handover protocol (or from firmware via the EFI
> >boot stub), but the kernel loader in Syslinux is smart enough to
> >fallback to the legacy scheme and just not use any of the EFI boot stub
> >code when mixing firmware/kernels.
> >
> During my tests, it did not work. When selecting a 32bit kernel
> entry, screen went black for about 2 seconds, then dropped back to
> Syslinux menu. 64bit kernel booted just fine.
> 
> Any further info I can give you to debug this? Are there any
> specific requirements for the kernel?
 
You could try running,

debug.c32 -e efi_boot_linux handover_boot

before executing your kernel. What kernel version are you using?

-- 
Matt Fleming, Intel Open Source Technology Center

Op 2013-07-11 om 16:17 schreef Matt Fleming:
> On Wed, 10 Jul, at 03:44:57PM, Andreas Heinlein wrote:
> > 
> > Any further info I can give you to debug this? Are there any
> > specific requirements for the kernel?
>  
> You could try running,
> 
> debug.c32 -e efi_boot_linux handover_boot
> 
> before executing your kernel.

Euh how? Where?

In a syslinux config file?
At the `boot:` prompt?

Please provide an example.


Regards
Geert Stappers
In an attempt to grasp the Syslinux dynamic debugger

> Op 2013-07-11 om 16:17 schreef Matt Fleming:
> > On Wed, 10 Jul, at 03:44:57PM, Andreas Heinlein wrote:
> > > 
> > > Any further info I can give you to debug this? Are there any
> > > specific requirements for the kernel?
> >  
> > You could try running,
> > 
> > debug.c32 -e efi_boot_linux handover_boot
> > 
> > before executing your kernel.
> 
> 
> Euh how? Where?
> 
> In a syslinux config file?
> At the `boot:` prompt?
> 
> Please provide an example.
> 
> 
> Regards
> Geert Stappers
> In an attempt to grasp the Syslinux dynamic debugger
> _______________________________________________
 
One way to do it would be as follows.

  *** syslinux.cfg start ***

# Avoid using [vesa]menu when debugging, unless _really_ necessary
#  so comment out any UI directive.
# Generic example; actual paths and names might need correction.

DEFAULT debug_module
PROMPT 1

LABEL debug_module
COM32 debug.c32
APPEND -e efi_boot_linux handover_boot
# actual debug parameters might be different for each case.

LABEL my_image
LINUX my_kernel.efi
INITRD my_initrd
APPEND my_additional_kernel_parameters
# correct paths where necessary

  *** syslinux.cfg start ***

1_ Boot (to prompt).
2_ Press [ENTER] (so 'debug_module' will be executed)
3_ Once again in the boot prompt, type in 'my_image' and press 
[ENTER].
4_ Take note, be patient, report feedback.

HTH,
Ady.

On Thu, 11 Jul, at 10:44:27PM, Geert Stappers wrote:
> Op 2013-07-11 om 16:17 schreef Matt Fleming:
> > On Wed, 10 Jul, at 03:44:57PM, Andreas Heinlein wrote:
> > > 
> > > Any further info I can give you to debug this? Are there any
> > > specific requirements for the kernel?
> >  
> > You could try running,
> > 
> > debug.c32 -e efi_boot_linux handover_boot
> > 
> > before executing your kernel.
> 
> 
> Euh how? Where?
> 
> In a syslinux config file?
> At the `boot:` prompt?
> 
> Please provide an example.
 
It needs a lot of work but an example is here,

http://www.syslinux.org/wiki/index.php/Development/Debugging#Syslinux_Dynamic_Debugger

-- 
Matt Fleming, Intel Open Source Technology Center