On Fri, Dec 01, 2006 at 07:28:53PM +0100, Stefan Reinauer wrote:
- Peter Stuge stuge-linuxbios@cdy.org [061201 19:16]:
The assumption was that not much needs to happen before the SPD I2C bus is accessible by the CPU - is that valid?
Since you need I2C, you need to get parts of the south bridge working.
Even though it's on the DIMM? Ugh. :(
So, its basically the same amount of work as with the USB debug port.
Yeah. Not much point to it then.
Question is: Will we see systems without USB (debug port) but with DDR2 sockets?
See wiki page with list of EHCI chips that lack the debug port. On the other hand maybe all boards using them will have a serial port?
If not, what IS easily accessible besides the boot ROM? (Which we don't want to rely on since we don't know exactly what it will speak when in the future.) We just need one bit that can do kHz signalling. SMI#?
Boot rom is a good start I bet. That will always be there (as long as we all do firmware development at least).
It might be parallel yesterday, LPC today and SPI tomorrow, but that is only the interface it connects to. Different connector, different VHDL source and we should be fine, no?
True. TSOPs are a bit unfriendly but still doable with a steady hand.
LPC is going away on many boards, I understand.
But DDR(2) SDRAM will probably stay a while longer. Or not?
If LPC goes away, we need to do SPI. Ok. If we get DDR3, we would have to do that. Technical standards come and go,.. I'd prefer a solution that is so cheap that I dont mind throwing the whole kit away after doing a port or two, rather than trying to create something that is good forever.
Me too. But the kit only gets that cheap if it can be produced in at least a run of 100. And while those are too small quantities for even receiving a quote from some suppliers it's already too big for us. :\
The testing infrastructure is the dealbreaker right now.
I think that we are going into a world where we have to figure out usb debug port.
It's certainly one good debugging option but maybe not the only good one.
Especially it does not help for reflashing. Finding something nifty here would be nice.
I hear you.
//Peter