On Sunday 01 July 2007 01:17:34 Lennert Buytenhek wrote: > More or less. You can't add the resistances like that, since the > bus isolation chip buffers the IDSEL signal, but it is correct that > if the host's IDSEL resistor is larger than a certain value, the > combination of the resistive coupling of IDSEL plus the extra buffer > in the isolator might be causing the IDSEL input on the 'guest' PCI > board to assert too late (or not assert at all), causing config > accesses to fail. > > (This also depends on the specific 'guest' PCI board used, as you > noted, due to differing IDSEL trace lengths/capacitances and input > pin capacitances on different PCI boards. Also, it might work at > 33 MHz but not work at 66 MHz, etc.)
It doesn't work on any of my boards :( > If you feel adventurous, you could try to hack around this by > figuring out which AD[31:16] line this PCI slot's IDSEL line is > resistively coupled to (depends on the slot), and then adding > another parallel resistor on the board itself to make the bus > isolator's input buffer charge faster. Note that this does > increase the load on that specific AD[] line, which might cause > other funny effects. Well, but how to find out to which address line it's connected to? Pretty hard to follow the PCB traces, especially since it's multilayered. -- Greetings Michael. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
