[U-Boot] CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE

[U-Boot] CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE

[anup behare]

Hi,

We are using taishan based board having 1GB DDR.
In u-boot code we found that CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE is set to
768MB hence "if (size < bootm_size)" condition becomes true and u-boot throw
"WARNING: adjusting available memory to 0x30000000" message on console.

Let me know will it possible to set CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE to 1GB
or is there any fix for above warning message?

Regards,
Anup

[U-Boot] CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE

[Stefan Roese]

Hi Anup,

On Tuesday 18 May 2010 09:03:25 anup behare wrote:
> We are using taishan based board having 1GB DDR.
> In u-boot code we found that CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE is set to
> 768MB hence "if (size < bootm_size)" condition becomes true and u-boot
> throw "WARNING: adjusting available memory to 0x30000000" message on
> console.
> 
> Let me know will it possible to set CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE to 1GB
> or is there any fix for above warning message?

Linux "lowmem" size is 768MB for PowerPC. Loading at a higher address results 
in a non-booting Linux kernel. So this warning makes sense and it's not 
possible to load to 1GB.

Why do you want to change this? Does this cause you any troubles? Is Linux not 
booting correctly? I don't see what you would "gain" by loading to 1GB.

Cheers,
Stefan

--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-0 Fax: (+49)-8142-66989-80 Email: office at denx.de

[U-Boot] CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE

[anup behare]

Hi  Stefan,


My intention was only to remove this warning.

My Linux is booting correctly and it is not causing any trouble but I
observed "WARNING: adjusting available memory to 0x30000000" on u-boot
console.

I have couple of question here with 768MB:

1. Is that mean u-boot will use only 768MB DDR?

2. What about kernel will it use complete DDR or will work with 768MB only?

3. Means we can?t remove this warning and this warning will come for DDR
more than 768MB?



~Anup


On Tue, May 18, 2010 at 1:37 PM, Stefan Roese <sr@denx.de> wrote:

> Hi Anup,
>
> On Tuesday 18 May 2010 09:03:25 anup behare wrote:
> > We are using taishan based board having 1GB DDR.
> > In u-boot code we found that CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE is set to
> > 768MB hence "if (size < bootm_size)" condition becomes true and u-boot
> > throw "WARNING: adjusting available memory to 0x30000000" message on
> > console.
> >
> > Let me know will it possible to set CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE to
> 1GB
> > or is there any fix for above warning message?
>
> Linux "lowmem" size is 768MB for PowerPC. Loading at a higher address
> results
> in a non-booting Linux kernel. So this warning makes sense and it's not
> possible to load to 1GB.
>
> Why do you want to change this? Does this cause you any troubles? Is Linux
> not
> booting correctly? I don't see what you would "gain" by loading to 1GB.
>
> Cheers,
> Stefan
>
> --
> DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-0 Fax: (+49)-8142-66989-80 Email: office at denx.de
>

[U-Boot] CONFIG_SYS_LINUX_LOWMEM_MAX_SIZE

[Stefan Roese]

Hi Anup,

On Tuesday 18 May 2010 11:24:42 anup behare wrote:
> My intention was only to remove this warning.

Perhaps it makes sense, to change this "WARNUNG:" to "NOTE:". I suggest you 
send a patch for this and we might accept it.
 
> My Linux is booting correctly and it is not causing any trouble but I
> observed "WARNING: adjusting available memory to 0x30000000" on u-boot
> console.
> 
> I have couple of question here with 768MB:
> 
> 1. Is that mean u-boot will use only 768MB DDR?

No.
 
> 2. What about kernel will it use complete DDR or will work with
> 768MB only?

That depends on your kernel configuration. For more than 768MB (lowmem) you 
need to enable highmem support of course.
 
> 3. Means we can?t remove this warning and this warning will come for DDR
> more than 768MB?

Yes. But we might change the text from "WARNING" to "NOTE" or something 
like this (see above).

Cheers,
Stefan

--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-0 Fax: (+49)-8142-66989-80 Email: office at denx.de