Re: [GIT PULL] On-demand device probing

From	Rob Clark <robdclark@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [GIT PULL] On-demand device probing
Date	2015-10-17 20:00 +0200
Message-ID	<qkDVU-4Kw-17@gated-at.bofh.it> (permalink)
References	(1 earlier) <qktDb-6d5-1@gated-at.bofh.it> <qkBho-14t-17@gated-at.bofh.it> <qkBU6-1Q7-15@gated-at.bofh.it> <qkCwN-2Pq-13@gated-at.bofh.it> <qkCZP-3ox-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Sat, Oct 17, 2015 at 12:56 PM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>> I'm guessing the time is a matter of probing and undoing the probes
>> rather than slow h/w. We could maybe improve things by making sure
>> drivers move what they defer on to the beginning of probe, but that
>> seems like a horrible, fragile hack.
>
> How can calling probe and failing cause 2 seconds?  How many different
> probe calls are failing here?  Again, a boot log graph would be great to
> see as it will show the root cause, not just guessing at this.

just fwiw, but when you have a driver that depends on several other
drivers (which in turn depend on other drivers and so on), the amount
of probe-defer we end up seeing is pretty comical.  Yeah, there
probably is some room to optimize by juggling around order drivers do
things in probe.  But that doesn't solve the fundamental problem with
the current state, about probe order having no clue about
dependencies..

BR,
-R
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Thread

[GIT PULL] On-demand device probing Tomeu Vizoso <tomeu.vizoso@collabora.com> - 2015-10-14 10:40 +0200
  Re: [GIT PULL] On-demand device probing Mark Brown <broonie@kernel.org> - 2015-10-14 11:30 +0200
    [GIT PULL] On-demand device probing Tomeu Vizoso <tomeu.vizoso@collabora.com> - 2015-10-15 13:50 +0200
      Re: [GIT PULL] On-demand device probing Olof Johansson <olof@lixom.net> - 2015-10-16 23:30 +0200
        Re: [GIT PULL] On-demand device probing Rob Herring <robh+dt@kernel.org> - 2015-10-17 17:30 +0200
  Re: [GIT PULL] On-demand device probing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-10-17 09:00 +0200
    Re: [GIT PULL] On-demand device probing Rob Herring <robh+dt@kernel.org> - 2015-10-17 17:10 +0200
      Re: [GIT PULL] On-demand device probing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-10-17 17:50 +0200
        Re: [GIT PULL] On-demand device probing Rob Herring <robh+dt@kernel.org> - 2015-10-17 18:30 +0200
          Re: [GIT PULL] On-demand device probing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-10-17 19:00 +0200
            Re: [GIT PULL] On-demand device probing Rob Clark <robdclark@gmail.com> - 2015-10-17 20:00 +0200
              Re: [GIT PULL] On-demand device probing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-10-17 20:30 +0200
                Re: [GIT PULL] On-demand device probing Rob Clark <robdclark@gmail.com> - 2015-10-17 20:50 +0200
                Re: [GIT PULL] On-demand device probing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-10-17 21:00 +0200
                Re: [GIT PULL] On-demand device probing Rob Clark <robdclark@gmail.com> - 2015-10-17 21:40 +0200
                Re: [GIT PULL] On-demand device probing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-10-17 22:30 +0200
                Re: [GIT PULL] On-demand device probing Noralf Trønnes <noralf@tronnes.org> - 2015-10-17 21:10 +0200
                Re: [GIT PULL] On-demand device probing Rob Clark <robdclark@gmail.com> - 2015-10-17 21:50 +0200

csiph-web