Re: PXA standby mode with SDRAM suspend (low power refresh)

["David Hunter" <hunterd42@xxxxxxxxx>]

On Wed, May 21, 2008 at 3:32 AM, Shane Volpe <shanevolpe@xxxxxxxxx> wrote:
> Has anyone modified (patched) the PXA standby code to put the SDRAM into
> self refresh mode, if so is there a patch available?  I want to have a
> system go into standby and put the SDRAM into self refresh to save power.
> suspend does this but it also shuts down the board so the boot loader must
> handle the wake up which is more complex and time consuming than I want.

I haven't tried it for myself, but it looks like standby.S and
pxa3xx.c do enter S0/D2/C2 on PM_SUSPEND_STANDBY. SDRAM should enter
self-refresh mode and the core should retain state.

If you end up in the bootloader, then maybe some external force is
resetting the CPU (e.g., watchdog).
-Dave

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