Kernel not detecting all of physical RAM in 1st generation Apple TV

Kernel not detecting all of physical RAM in 1st generation Apple TV

[Bharath Ramesh]

I am trying to get a minimal kernel config running on a 1st generation
Apple TV to compile the kernel so that I can have it detect all of the
256MB of RAM the device has. A brief summary to get Linux booting on
the 1st generation Apple TV requires the use of the atv-bootloader
project [1]. The 1st generation Apple TV uses EFI and the
atv-bootloader project translates EFI structures to standard PC BIOS
structures. The issue I am facing is that kernel doesnt always detect
the entire 256MB of RAM that the Apple TV has. With a very minimal
change in the kernel config I can cause the kernel not to detect the
entire 256MB of RAM. I have test config along with the respective
dmesg output which shows this issue. This was not the case with the
earlier 2.6.24 kernel that I am running, the 2.6.24 kernel is a Ubuntu
8.04 distribution kernel. The following config and dmesg is using
kernel.org source.

config-3.2.18-nouveau-256M: http://pastebin.com/9V8dSED3
config-3.2.18-nouveau-64M: http://pastebin.com/CsUK0yy3
config.3.2.18-nouveau-256M-64M.diff: http://pastebin.com/MkYbQf5V
dmesg.3.2.18-nouveau-256M: http://pastebin.com/UUYBzqm8
dmesg.3.2.18-nouveau-64M: http://pastebin.com/FDntUsfd
dmesg.3.2.18-nouveau-256M-64M.diff: http://pastebin.com/2myAa9Z0

Any help in debugging this issue that I can get the kernel to always
detect all of the RAM would be greatly appreciated. I am not
subscribed to the list, would greatly appreciate it if I am copied in
the response.

Thanks,

Bharath

[1] http://code.google.com/p/atv-bootloader/

Re: Kernel not detecting all of physical RAM in 1st generation Apple TV

[Damián Gatabria]

I've hit the same problem; 3.4.4 still only uses 64MB of memory, even
though it detects all 256MB of it. Could anybody please at least
review the kernel config provided by Bharath and let us know if
there's anything obviously wrong with it or if this is expected
behavior for some reason?


Thank you.



On Mon, Jun 25, 2012 at 10:52 PM, Bharath Ramesh <bramesh.dev@gmail.com> wrote:
>
> I am trying to get a minimal kernel config running on a 1st generation
> Apple TV to compile the kernel so that I can have it detect all of the
> 256MB of RAM the device has. A brief summary to get Linux booting on
> the 1st generation Apple TV requires the use of the atv-bootloader
> project [1]. The 1st generation Apple TV uses EFI and the
> atv-bootloader project translates EFI structures to standard PC BIOS
> structures. The issue I am facing is that kernel doesnt always detect
> the entire 256MB of RAM that the Apple TV has. With a very minimal
> change in the kernel config I can cause the kernel not to detect the
> entire 256MB of RAM. I have test config along with the respective
> dmesg output which shows this issue. This was not the case with the
> earlier 2.6.24 kernel that I am running, the 2.6.24 kernel is a Ubuntu
> 8.04 distribution kernel. The following config and dmesg is using
> kernel.org source.
>
> config-3.2.18-nouveau-256M: http://pastebin.com/9V8dSED3
> config-3.2.18-nouveau-64M: http://pastebin.com/CsUK0yy3
> config.3.2.18-nouveau-256M-64M.diff: http://pastebin.com/MkYbQf5V
> dmesg.3.2.18-nouveau-256M: http://pastebin.com/UUYBzqm8
> dmesg.3.2.18-nouveau-64M: http://pastebin.com/FDntUsfd
> dmesg.3.2.18-nouveau-256M-64M.diff: http://pastebin.com/2myAa9Z0
>
> Any help in debugging this issue that I can get the kernel to always
> detect all of the RAM would be greatly appreciated. I am not
> subscribed to the list, would greatly appreciate it if I am copied in
> the response.
>
> Thanks,
>
> Bharath
>
> [1] http://code.google.com/p/atv-bootloader/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/