Re: [PATCH v2] char drivers: Ram oops/panic logger

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

 



On Fri, Mar 12, 2010 at 23:48, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 10 Mar 2010 13:15:25 +0100
> Marco Stornelli <marco.stornelli@xxxxxxxxx> wrote:
>
>> 2010/3/10 Yuasa Yoichi <yuasa@xxxxxxxxxxxxxx>:
>> > 2010/3/10 Marco Stornelli <marco.stornelli@xxxxxxxxx>:
>> >> 2010/3/10 Yuasa Yoichi <yuasa@xxxxxxxxxxxxxx>:
>> >>> Hi,
>> >>>
>> >>> 2010/3/10 Marco Stornelli <marco.stornelli@xxxxxxxxx>:
>> >>>> Ramoops, like mtdoops, can log oops/panic information but in RAM.
>> >>>
>> >>> What is different from mtdoops + mtd-ram?
>> >>>
>> >>> Yoichi
>> >>>
>> >>
>> >> It can be used in a very easy way with persistent RAM for systems
>> >> without flash support. For this systems, with this driver, it's no
>> >> more needed add to the kernel the mtd subsystem with advantage in
>> >> footprint as I said in the description.
>> >
>> > right.
>> > But,
>> >
>> >> In addition, you can save
>> >> flash space and store this information only in RAM. I think it's very
>> >> useful for embedded systems.
>> >
>> > CONFIG_MTD_RAM uses only RAM.
>> > I think there's no big difference about this point.
>> >
>>
>> I meant with the "classic" use of mtdoops, therefore with a flash
>> partition without use MTD_RAM. Using MTD_RAM, it's more or less the
>> same thing, with the exception of "where" you want deploy the log. For
>> example: if in your system you have got a nvram you can use it without
>> problem, you need to specify the address of the nvram to the module.
>> Very simple. I  think it's a small driver but very useful, feedback
>> from other embedded guys are welcome.
>
> Seems sensible to me.  If you have a machine whose memory is persistent
> across reboots then you reserve an arbitrary 4k hunk of memory for
> collecting oops traces, yes?
>
> What tools are used for displaying that memory on the next boot?  How
> do those tools distinguish between "valid oops trace" and "garbage
> because it was just powered on"?  A magic signature?

On Amiga, `debug=mem' enables something like that, cfr. git grep dmesg
arch/m68k.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-embedded" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Gstreamer Embedded]     [Linux MMC Devel]     [U-Boot V2]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux ARM Kernel]     [Linux OMAP]     [Linux SCSI]

  Powered by Linux