Hi,
I work for a small company as a hardware developer and they developed a product through a consulting firm that basically consists of a PCIe to PCI bridge to interface to the laptop PCI express and another PCI enabled chip connected to that local PCI bus. Although I was not here for the initial developement, it appears that the bios in a fairly significant number of laptops does not properly set up the bridge chip and/or downstream device (neither requires a driver).
I have talked to a major PCI bridge manufacturer regarding this and while they did not have much comment on the PCMCIA, they did say that they test their bridge chips on as many desktop systems as possible and they typically can only find one or 2 bios/chipset issues.
So I'm thinking that some laptop bios' writers made a decision that they would not support bridges on the PCMCIA or perhaps it was not tested throughly. I have removed the cover on some simple PCMCIA cards that have dual functions (say firewire + usb) and they do not use bridges - the functions are simply paralled on the PCMCIA bus (PCMCIA in cardbus mode is essentially identical to PCI in case you did not know).
BTW, the errors we typically get are Code 12 (insufficient resources) or some laptops report that only 16 bit PC Card is supported when our hardware is inserted.
So just to summarize,my contention is that:
1. Many Laptop bios' may not support or may not properly support bridges on the PCI (PMCIA or PCIe (expresscard).
2. Although I have only cracked open a few, it appears that PCMCIA cards that have functions that require 2 or more PCI enabled chips normally implement them in parallel as opposed to a bridge (former is actually cheaper in the case of 2 chips anyhow).
3. The lack of PCMCA cards with bridges has not spurred the bios writers to implement or test bridge support on the PCMCA/expresscard interface (ie it's a vicious cycle).
Is my reasoning sound?
Thanks
I work for a small company as a hardware developer and they developed a product through a consulting firm that basically consists of a PCIe to PCI bridge to interface to the laptop PCI express and another PCI enabled chip connected to that local PCI bus. Although I was not here for the initial developement, it appears that the bios in a fairly significant number of laptops does not properly set up the bridge chip and/or downstream device (neither requires a driver).
I have talked to a major PCI bridge manufacturer regarding this and while they did not have much comment on the PCMCIA, they did say that they test their bridge chips on as many desktop systems as possible and they typically can only find one or 2 bios/chipset issues.
So I'm thinking that some laptop bios' writers made a decision that they would not support bridges on the PCMCIA or perhaps it was not tested throughly. I have removed the cover on some simple PCMCIA cards that have dual functions (say firewire + usb) and they do not use bridges - the functions are simply paralled on the PCMCIA bus (PCMCIA in cardbus mode is essentially identical to PCI in case you did not know).
BTW, the errors we typically get are Code 12 (insufficient resources) or some laptops report that only 16 bit PC Card is supported when our hardware is inserted.
So just to summarize,my contention is that:
1. Many Laptop bios' may not support or may not properly support bridges on the PCI (PMCIA or PCIe (expresscard).
2. Although I have only cracked open a few, it appears that PCMCIA cards that have functions that require 2 or more PCI enabled chips normally implement them in parallel as opposed to a bridge (former is actually cheaper in the case of 2 chips anyhow).
3. The lack of PCMCA cards with bridges has not spurred the bios writers to implement or test bridge support on the PCMCA/expresscard interface (ie it's a vicious cycle).
Is my reasoning sound?
Thanks
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