[lkml]   [2004]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: suspend/resume support for driver requires an external firmware

On Fri, 24 Sep 2004, Zhu, Yi wrote:

> Choice 1. In 2.5 kernel, there used to be a ->save_state method in the
> device PM interface. From the "not yet updated" document
> (Documentation/power/pci.txt), this function can be used as "a notification
> that it(the device) may be entering a sleep state in the near future". If we
> take back this interface, the problem can be solved. That is, the driver
> loads firmware into memory in ->save_state and frees the memory in ->resume.
> The deadlock is resolved without any runtime memory wasted.
> patch embeded at the end of the mail.

We talked about this in Ottawa a few months ago, and I think this is the
right approach. Note though, that I think it needs to be more complete:

- There needs to be restore_state() to be symmetic.
- There needs to be the proper failure recovery
If save_state() or suspend() fails, every device that has had their
state saved needs to be restored.
- It needs to be called for all power management requests.
- The PCI implementation should call pci_save_state() in it, instead of in

It would be great if you could add these things. Otherwise, I'll add it to
my TODO list..


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 14:06    [W:0.046 / U:2.136 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site