Re: [PATCH] sky2: override for PCI legacy power management

On Wed, Mar 21, 2012 at 2:47 PM, Stephen Hemminger
[off-list ref] wrote:

On Wed, 21 Mar 2012 14:22:01 -0600
Bjorn Helgaas [off-list ref] wrote:

quoted

On Wed, Mar 21, 2012 at 9:32 AM, Stephen Hemminger
[off-list ref] wrote:

quoted

Some BIOS's don't setup power management correctly (what else is
new) and don't allow use of PCI Express power control. Add a special
exception module parameter to allow working around this issue.
Based on slightly different patch by Knut Petersen.

Reported-by: Arkadiusz Miskiewicz <redacted>
Signed-off-by: Stephen Hemminger <redacted>

Is there a problem report URL you can include here?

It looks like this requires a user to figure out that he might be
suffering from this problem, then use this module parameter to work
around it.  How would a user figure that out?  Can we do it
automatically to save him the trouble?

I am not a power management expert. Looks like a BIOS issue where the
BIOS has configured the device to disable power management but the
user wants to override that value. There is no method to determine
when the BIOS is broken versus when the BIOS setting is correct and
we should follow what it says.

I'm not a power management expert either.  I was just wondering
whether the known broken BIOSes could be encoded in a blacklist or
something, because it looks like a case where a user might have to
request help or debug the problem again before discovering this flag.

Bjorn