Re: [PATCH 4/4] PCI: make cardbus-bridge resources nice-to-have

[Jesse Barnes]

On Tue, 21 Jun 2011 09:23:21 -0700
Ram Pai <linuxram@xxxxxxxxxx> wrote:

> On Tue, Jun 21, 2011 at 09:57:00AM +0200, Dominik Brodowski wrote:
> > On Mon, Jun 20, 2011 at 03:47:17PM -0700, Ram Pai wrote:
> > > Allocate resources to cardbus bridge only after all other genuine
> > > resources requests are satisfied. Dont retry if resource allocation
> > > for cardbus-bridge fails.
> > 
> > Well, for those who use cardbus cards, cardbus resources aren't "nice to
> > have", they are absolutely required. Of course, not all cardbus cards need
> > as many resources as are currently assigned, so I wouldn't oppose a patch
> > which marks _some_ of the currently assigned resources as "nice to have".
> > But this approach -- 0 required, all "nice to have" -- seems wrong to me.
> 
> Do you know how much minimal resource is good enough?  The value, before
> this patch, was 256 for IO ports and  64M for memory.
> 
> BTW: If the BIOS has already assigned enough resources for all the devices on
> the system, no devices will be starved including the cardbus. The OS intervenes
> and is forced to make this hard choice only when it sees unassigned resources to
> some devices along with resource contention.

Dominik, presumably you have a few good cardbus test machines; can you
give Ram's patches a try?  If we know they break existing
configurations, I'm afraid we'll just have to revert the whole
re-allocation patch yet again.  If your stuff survives, I'll ping Linus
to see what he thinks, though he'll probably want to revert in any
case...

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center
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