Messages in this thread | | | Date | Tue, 23 Nov 1999 10:42:40 -0500 (EST) | From | Donald Becker <> | Subject | Hot PCI bus plugging |
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There is little operational difference between hot-swap PCI and CardBus. And some of us have been be working with CardBus devices for years. For instance, see http://cesdis.gsfc.nasa.gov/linux/drivers/kern-2.3/index.html
If you consider the issues, CardBus is actually a more difficult environment. The driver must contend with switching between two incompatible signaling schemes (PCMCIA is ISA-like), reading an overly complicated CIS, setting the voltages and timings according to what was read from the CIS, and rapid insert/eject cycles(*).
Both hot-swap PCI and CardBus require multiple logical bus bridges that can disconnect the signal leads and turn off power to just one slot, so don't try hot-plugging cards on your standard desktop machine!
* IBM's hot-swap implementation sends an "eject" signal when you pivot the PCI card hold-down. There is plenty of time before the card is removed. In contrast, CardBus drivers must deal with the card going away without warning, or a barely-inserted card that is activated many times a second.
Donald Becker Scyld Computing Corporation becker@tidalwave.net 240-463-0035 (voice) Columbia MD
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