Fwd: Fwd: New feature: a "poweroff" command

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



I cannot give a general definition of "embedded systems", but for sure
I can explain my concern : my project (= hobby) is to run ELKS on this
SBC : http://www.advantech.com/products/1-2jkp2y/snmp-1000-b/mod_b01abe8d-c8aa-4530-8e3c-9fcd2623d9d6

It was primarily intended for remote PC HW control / monitoring
(Telnet, HTTP, SNMP, etc) but it can easily be hacked as it is based
on a 80188 / PC architecture, and has a removable Flash that can be
reprogrammed easily with SW protocol. Moreover it has an ETH
interface, plenty of I/O pins, and I can find several of them in my
company garbage containers :-).

In the Flash, the manufacturer (Advantech) implemented a firmware
clearly derived from a PC BIOS, but with uggly shortcuts (like
redirecting the BIOS 10h to serial, or reusing some standard INT
numbers without compliance to the IBM BIOS reference, etc). You can
have a look to the EMU86 INT emulation to get an idea of how far this
BIOS is away from the standard :
https://github.com/jbruchon/dev86/blob/master/emu86/emu-int.c

This is why, in such situation, if Jody's adds invocation of the BIOS
15h in ELKS, it should be surrounded by a configuration option,
otherwise I would have to add an INT 15h handler in the Flash to
return CF=1. If even if I would like to implement the power control, I
see no HW facility on the board to cut its own power supply (= passive
voltage adapter) without adding an external circuit.

MFLD



2016-05-26 11:40 GMT+02:00 Kirn Gill <segin2005@xxxxxxxxx>:
> I'm not 100% on the linguistics, but can you please explain what you meant
> about embedded systems? Do you mean ones without a BIOS?
>
> Wouldn't it make more sense to tie this feature to a build target (e.g. PC
> and not embedded) instead of it's own config switch?
>
> I suppose this will make for a good learning experience for me.
>
> On May 26, 2016 04:34, "Marc-François LUCCA-DANIAU" <mfld.fr@xxxxxxxxx>
> wrote:
>>
>> IMHO, this feature makes sense for emulators intended for end-user,
>> that try to mimic a real PC with a full-featured BIOS,but raises an
>> issue for the embedded devices, because it forces to implement BIOS
>> 15h, at least a stub to return with CF set.
>>
>> For that reason, I would enhance your change by adding something like
>> an "BIOS power management" option in the ELKS configuration
>> (CONFIG_BIOS_POWER ?).
>>
>> MFLD
>>
>>
>> 2016-05-26 3:51 GMT+02:00 Jody Bruchon <jody@xxxxxxxxxxxxxxx>:
>> > I have just committed a 'poweroff' command to ELKS. Piggybacking on the
>> > existing sys_reboot() syscall, the commit uses Advanced Power Management
>> > (APM) BIOS calls to power down the computer when the poweroff command is
>> > issued. If you're running in an emulator like QEMU, Bochs, or
>> > Virtualbox, or
>> > if you're running ELKS on any APM-enabled platform such as most 486 or
>> > higher laptops and any older ATX PC, this is a much more convenient way
>> > to
>> > shut down.
>> >
>> > I find this to be a nicer way of exiting the QEMU curses interface than
>> > ESC,
>> > 2, q, [enter] in any case, and most ELKS testing seems to be done on
>> > more
>> > modern systems and emulators, so it makes sense. I would like someone to
>> > test it on a non-APM system to make sure that a failure due to no APM
>> > support falls through to an error message.
>> >
>> > Also, I am thinking of renaming sys_reboot() to sys_shutdown() to better
>> > reflect its actual purpose. Any objections?
>> >
>> > -Jody
>> > --
>> > To unsubscribe from this list: send the line "unsubscribe linux-8086" in
>> > the body of a message to majordomo@xxxxxxxxxxxxxxx
>> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-8086" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-8086" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel]     [Linux ia64]     [DCCP]     [Linux for ARM]     [Yosemite News]     [Linux SCSI]     [Linux Hams]

  Powered by Linux