Re: [PATCH 18/25] ohci1394: Fix broken suspend/resume in ohci1394

[Stefan Richter]

Chris Wright wrote:
...
> From: Robert Hancock <hancockr@xxxxxxx>
...
> I created the patch below and tested it, and it appears to resolve the
> suspend problems I was having with the module loaded. I only added in
> the pci_save_state and pci_restore_state - however, though I know little
> of this hardware, surely the driver should really be doing more than
> this when suspending and resuming? Currently it does almost nothing,
> what if there are commands in progress, etc?
...

This patch is OK. (Although unlike one might expect from reading the 
patch title, there is still a lot to do for full suspend/resume 
functionality in ohci1394.) Just FYI, here is my reply to Robert's 
initial patch submission:

| Thanks, this is at least a start. Apart from the code for PPC Macintoshs,
| ohci1394 does indeed lack any suspend/resume handling. I don't know
| anything about this matter, however the OHCI spec (gratis available,
| linked from www.linux1394.org) table A-11 on page 168 says which losses
| of configuration result from what power state transitions: Interrupts are
| masked when going into D1. IEEE 1394 configuration is lost when going
| into D2. PCI configuration is lost when going into D3. Since we don't
| handle this yet, a suspend/resume cycle results at least in loss of
| FireWire connectivity.
|
| As you may have guessed, this problem is basically as old as the driver.
| Nobody is actively working on it AFAIK. ["it" = the resume problem]
| (Except that I dusted off an old notebook and put a fresh Linux distro on
| it --- with the plan [to] check power management and hot ejection
| handling by ohci1394... later this year...)
--
Stefan Richter
-=====-=-==- -==- ==-==
http://arcgraph.de/sr/
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