Messages in this thread | | | Subject | Re: [PATCH v2] driver core: add a debugfs entry to show deferred devices | From | Javier Martinez Canillas <> | Date | Sun, 8 Jul 2018 02:31:49 +0200 |
| |
Hi Greg,
On 07/07/2018 05:59 PM, Greg Kroah-Hartman wrote: > On Thu, Jun 28, 2018 at 12:06:56AM +0200, Javier Martinez Canillas wrote: >> With Device Trees (DT), the dependencies of the devices are defined in the >> DT, then the drivers parse that information to lookup the needed resources >> that have as dependencies. >> >> Since drivers and devices are registered in a non-deterministic way, it is >> possible that a device that is a dependency has not been registered yet by >> the time that is looked up. >> >> In this case the driver that requires this dependency cannot probe and has >> to defer it. So the driver core adds it to a list of deferred devices that >> is iterated again every time that a new driver is probed successfully. >> >> For debugging purposes it may be useful to know what are the devices whose >> probe function was deferred. Add a debugfs entry showing that information. >> >> $ cat /sys/kernel/debug/devices_deferred >> 48070000.i2c:twl@48:bci >> musb-hdrc.0.auto >> omapdrm.0 >> >> This information could be obtained partially by enabling debugging, but it >> means that the kernel log has to be parsed and the probe deferral balanced >> with the successes. This can be error probe and has to be done in a ad-hoc >> manner by everyone who needs to debug these kind of issues. >> >> Since the information is already known by the kernel, just show it to make >> it easier to debug. >> >> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> >> Reviewed-by: Mark Brown <broonie@kernel.org> > > This doesn't apply to my tree anymore :( >
I see, I made sure that it applied on top of linux-next.
> Can you rebase and resend? >
I guess you want me to rebase on top of your driver-core-next branch. I think that linux-next should pull that branch instead of the driver-core-linus one:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Next/Trees#n29
> thanks, > > greg k-h >
Best regards, -- Javier Martinez Canillas Software Engineer - Desktop Hardware Enablement Red Hat
| |