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Author Message
 Enhance CPCI Hot Swap driver
Hi, Scott,
After reading your CPCI Hot Swap support codes, I have a suggestion
to enhance it:
How about to make it be full hot swap compliant?
I mean we could also do some works like "disable_slot" when we receive
the #ENUM & EXT signal. Hence the user could yank the hot swap board
without issuing command on the console.
How do you think about it?

Cheers,
-Stan
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 Sun, 17 Jul 2005 09:00:26 GMT   
 Enhance CPCI Hot Swap driver

How does this behavior translate to "full hot swap compliant"?  I assume
you are talking about wording from PICMG 2.16, which in my opinion
describes the full software stack, not just the driver.  Any kind of
full CPCI solution would have all the user space components to
coordinate disabling a slot before the operator physically yanks the
board (and therefore behave as PICMG specifies).  I'm not so sure the
driver knows enough to make a policy decision on what to do when an
operator bypasses the world and just yanks a board out with no warning.

    --rustyl

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 Sun, 17 Jul 2005 17:40:24 GMT   
 Enhance CPCI Hot Swap driver

Since most hardware devices need some form of userspace cleanup before
they can be removed, the separation of notification and extraction is
on purpose in the current cPCI hotplug driver.  Full Hot Swap compliance
per the PICMG 2.1 R2.0 specification can be achieved through the use of
a daemon in userspace that:

1) detects extract requests, either through the directory notifications
   sent by pci_hp_update_slot_info, or by simple polling of the latch and
   adapter files.
2) does the desired userspace cleanup.
3) completes the extraction by writing 0 to the slot's power file.

For reference, I'm putting the GPL'd userspace daemon I wrote for use in
our product here at SOMA on our download site at:

ftp://oss.somanetworks.com/pub/linux/cpci/pcihotplugd/pcihotplugd-200...

Note that it requires the directory notifications provided by calling
pci_hp_change_slot_info, so your sysfs patch will keep it from working
correctly.

Scott

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Scott Murray
SOMA Networks, Inc.
Toronto, Ontario
e-mail: sco...@somanetworks.com

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 Sun, 17 Jul 2005 19:30:08 GMT   
 Enhance CPCI Hot Swap driver
On 28 Jan 2003, Rusty {*filter*} wrote:

Slight nitpick, I'm pretty sure you mean PICMG 2.12 here, it's the  
(somewhat lame IMO :) hotswap software spec, 2.16 is the packet switched
backplane stuff.

Exactly.

Scott

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Scott Murray
SOMA Networks, Inc.
Toronto, Ontario
e-mail: sco...@somanetworks.com

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 Sun, 17 Jul 2005 19:30:16 GMT   
 Enhance CPCI Hot Swap driver

How is this functionally different from ejecting a PCMCIA card in use? Is
the driver obligated to do more than prevent a system crash and present
errors to user level until the last close?

Ed
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 Sun, 17 Jul 2005 21:00:09 GMT   
 Enhance CPCI Hot Swap driver

cPCI hotswap as defined in the PICMG 2.1 specification is a different
beast from PCMCIA because it was purposely defined to give software a
chance to do something before the device disappears.  The specification
even goes so far as to say that the system is in an undefined state if
a device is yanked without waiting for the system software indicating it
is safe to do so.  In reality, handling someone yanking a board is indeed
desireable, although it seems unlikely that the vast array of PCI device
drivers will ever get updated to handle it.

Scott

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Scott Murray
SOMA Networks, Inc.
Toronto, Ontario
e-mail: sco...@somanetworks.com

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 Sun, 17 Jul 2005 23:20:10 GMT   
 Enhance CPCI Hot Swap driver

Yeah, I mean PCIMG 2.12 here.

Regards,
-Stan
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 Mon, 18 Jul 2005 01:50:03 GMT   
 Enhance CPCI Hot Swap driver

Yes, I think this is the proper way to be compliant to PICMG 2.1.
Many thanks to you all.

Best Regards,
-Stan

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 Mon, 18 Jul 2005 01:50:11 GMT   
 
   [ 12 post ] 

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