lkml.org 
[lkml]   [2013]   [Nov]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] of/platform: Fix no irq domain found errors when populating interrupts
* Thierry Reding <thierry.reding@gmail.com> [131125 01:51]:
> On Mon, Nov 25, 2013 at 10:25:50AM +0100, Thierry Reding wrote:
> > On Sun, Nov 24, 2013 at 09:36:51PM +0000, Grant Likely wrote:
> > >
> > > I actually like the idea of completely allocating the resource structure
> > > but leaving some entries empty. However, I agree with rmk that putting
> > > garbage into a resource structure is a bad idea. What about changing the
> > > value of flags to 0 or some other value to be obviously an empty
> > > property and give the follow up parsing some context about which ones it
> > > needs to attempt to recalculate?
> >
> > When I worked on this a while back I came to the same conclusion. It's
> > nice to allocate all the resources at once, because the number of them
> > doesn't change, only their actually values.
>
> I should maybe add: one issue that was raised during review of my
> initial patch series was that we'll also need to cope with situations
> like the following:
>
> 1) device's interrupt parent is probed (assigned IRQ base X)
> 2) device is probed (interrupt parent there, therefore gets
> assigned IRQ (X + z)
> 3) device in removed
> 4) device's interrupt parent is removed
> 5) device is probed (deferred because interrupt parent isn't
> there)
> 6) device's interrupt parent is probed (assigned IRQ base Y)
> 7) device is probed, gets assigned IRQ (Y + z)
>
> So not only do we have to track which resources are interrupt resources,
> but we also need to have them reassigned everytime the device is probed,
> therefore interrupt mappings need to be properly disposed and the values
> invalidated when probing is deferred or the device removed.
>
> Having a dynamic list of properties all of a sudden doesn't sound like
> such a bad idea after all. It makes handling this kind of situation
> rather trivial, especially per-type lists. Those lists will be empty at
> first and populated during the first probe. When probing fails or when a
> device is unloaded, we dispose the mappings and empty the lists, so that
> subsequent probes will start from scratch. It certainly sounds like a
> bit of a waste of CPU cycles, but on the other hand it makes the code
> much simpler.

Looks like we cannot yet use devm_allocate, but that seems like a nice
solution in the long run. I just posted an updated patch to fix the $Subject
bug for the -rc cycle to this thread with more comments regarding dynamically
allocating the resources.

Regards,

Tony


\
 
 \ /
  Last update: 2013-11-25 21:41    [W:0.089 / U:0.136 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site