Mark Lord wrote:
I have a Dell notebook with an PCIe ExpressCard slot.
I also have a PCIe ExpressCard SATA controller (uses sata_sil24 driver).
I would like to be able to hot plug/unplug the controller card at will.
But alas, Linux doesn't cope with it *unless* I boot the kernel with
the card initially inserted.
1. Booting Linux kernel (latest 2.6.23) without the card inserted
means that the card will never be detected, regardless of how many
times subsequently the card is inserted/removed/whatever.
2. Booting Linux kernel *with* the card inserted means that it is
detected and used, and can be unplugged/replugged as I please,
with intervening suspend/resume (RAM or disk) cycles not interfering.
3. Booting Linux kernel without the card inserted, and then doing
a suspend-to-disk poweroff, inserting the card, and powering on again,
the card's BIOS extension runs as normal. But on resume from the
suspend-to-disk, the running kernel again never sees the card,
even after removing/reinserting/whatever.
4. All of this leads me to believe that the kernel must be doing some
kind of once-only scan of hardware at boot time, and never repeating
it afterwards. Loading/unloading all of the PCI/PCIe hotplug stuff
has no effect on this, so it must be broken elsewhere.
5. It is not likely to be a BIOS thing, because it still fails on
power-on (with card inserted) after a suspend-to-disk, which appears
to the BIOS exactly the same as any other power-on.
6. But it's probably a "kernel relies on BIOS data structure read
at boot time" issue, based on the observations above.
Actually, I must now take back some of that.
Most of these tests were done a month or two ago.
With 2.6.23.1 running, I just now redid all of the tests.
Now it seems that pciehp fails to notice a newly inserted card
only after a suspend/resume cycle with the slot empty.
I can now get it to work again by just doing:
1. remove the card, so the slot is empty.
2. rmmod pciehp; modprobe pciehp
3. insert the card again -- it works!
So we just need to fix an issue or two with suspend/resume (RAM) in pciehp.
Cheers
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