On Mon, Feb 06, 2017 at 05:34:07PM +0000, Russell King - ARM Linux wrote:
> On Mon, Feb 06, 2017 at 05:23:06PM +0000, Liviu Dudau wrote:
> > On Mon, Feb 06, 2017 at 11:09:49AM -0600, Rob Herring wrote:
> > > On Mon, Feb 06, 2017 at 10:29:33AM +0000, Liviu Dudau wrote:
> > > > On Fri, Feb 03, 2017 at 09:36:33PM -0600, Rob Herring wrote:
> > > > > - /* add the remote encoder port as component */
> > > > > - port = of_graph_get_remote_port_parent(ep);
> > > > > - of_node_put(ep);
> > > > > - if (!port || !of_device_is_available(port)) {
> > > > > - of_node_put(port);
> > > > > - return -EAGAIN;
> > > >
> > > > The HDLCD change looks reasonable except for this -EAGAIN business. I'll have to
> > > > test your changes on my setup to see how this affects having the encoder as a module.
> > >
> > > What are you expecting to happen with -EAGAIN? This one was a bit of an
> > > oddball.
> >
> > When both the HDLCD and the TDA998x drivers are compiled as modules, the
> > order in which they are inserted can be somewhat random (due to testing).
>
> Not really "due to testing" but if you run a real distro, they tend to
> have a multi-threaded behaviour when loading kernel modules at boot.
Yeah, a lot of times I'm using a toy "distribution" (buildroot) as it boots
faster under ARM models than a "real" (read systemd-based) distro would.
>
> > It is at that time when you want the probe of HDLCD to be retried on the
> > insmod-ing of the tda998x.ko rather than fail entirely.
>
> -EAGAIN doesn't get you that, and in any case, solving that problem is
> exactly why the component API exists - so that DRM only comes up once
> all the necessary components are available.
>
> -EAGAIN also doesn't get you that from inside a probe function - such
> an error will be reported in the kernel log, and no further action
> will be taken (the device driver probe will be failed, and not
> automatically retried.
I stand corrected on the behaviour of the driver then. That was the original
intent, to generate a re-probe of the driver.
>
> The only case that we automatically retry is if a driver returns
> -EPROBE_DEFER. Everything else causes a probe failure.
OK, I will fix the driver if Rob's patch still requires it.
Best regards,
Liviu
>
> --
> RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
> FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
> according to speedtest.net.
--
====================
| I would like to |
| fix the world, |
| but they're not |
| giving me the |
\ source code! /
---------------
¯\_(ツ)_/¯
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