Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion

From	"Luis R. Rodriguez" <mcgrof@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion
Date	2016-08-03 18:10 +0200
Message-ID	<s26U1-4HD-3@gated-at.bofh.it> (permalink)
References	(5 earlier) <s1AUa-jn-19@gated-at.bofh.it> <s1BwS-LI-3@gated-at.bofh.it> <s1BQe-TD-13@gated-at.bofh.it> <s1CMh-1vQ-5@gated-at.bofh.it> <s1Z6a-863-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Aug 03, 2016 at 12:42:14AM -0700, Dmitry Torokhov wrote:
> On Tue, Aug 2, 2016 at 12:41 AM, Luis R. Rodriguez <mcgrof@kernel.org> wrote:
> > On Tue, Aug 02, 2016 at 08:53:55AM +0200, Daniel Wagner wrote:
> >> On 08/02/2016 08:34 AM, Luis R. Rodriguez wrote:
> >> >On Tue, Aug 02, 2016 at 07:49:19AM +0200, Daniel Wagner wrote:
> >> >>>The sysdata API's main goal rather is to provide a flexible API first,
> >> >>>compartamentalizing the usermode helper was secondary. But now it seems
> >> >>>I may just also add devm support too to help simplify code further.
> >> >>
> >> >>I missed the point that you plan to add usermode helper support to
> >> >>the sysdata API.
> >> >
> >> >I had no such plans, when I have asked folks so far about "hey are you
> >> >really in need for it, OK what for? " and "what extended uses do you
> >> >envision?" so I far I have not gotten any replies at all. So -- instead
> >> >sysdata currently ignores it.
> >>
> >> So you argue for the remoteproc use case with 100+ MB firmware that
> >> if there is a way to load after pivot_root() (or other additional
> >> firmware partition shows up) then there is no need at all for
> >> usermode helper?
> >
> > No, I'm saying I'd like to hear valid uses cases for the usermode helper and so
> > far I have only found using coccinelle grammar 2 explicit users, that's it. My
> > patch series (not yet merge) then annotates these as valid as I've verified
> > through their documentation they have some quirky requirement.
> 
> In certain configurations (embedded) people do not want to use
> initramfs nor modules nor embed firmware into the kernel. In this case
> usermode helper + firmware calss timeout handling provides necessary
> wait for the root filesystem to be mounted.
> 
> If we solve waiting for rootfs (or something else that may contain
> firmware) then these cases will not need to use usermode helper.

Given most distributions already disable FW_LOADER_USER_HELPER_FALLBACK and
grammar shows we only have 2 explicit users of the usermode helper I'd
prefer if we indeed could just compartamentalize the usermode helper
and not rely on it further. Furthermore I think its possible address
this issue, and suggested at least one idea how for now. With a bit
further review I'm in hope we can address this well, not only
for the firmware API but for all other kernel_read_file*() users.

  Luis

Thread

[RFC v0 0/8] Reuse firmware loader helpers Daniel Wagner <wagi@monom.org> - 2016-07-28 10:00 +0200
  [RFC v0 8/8] iwl4965: use firmware_stat instead of completion Daniel Wagner <wagi@monom.org> - 2016-07-28 10:00 +0200
  [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion Daniel Wagner <wagi@monom.org> - 2016-07-28 10:00 +0200
    Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-07-28 20:40 +0200
      Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Bjorn Andersson <bjorn.andersson@linaro.org> - 2016-07-28 21:10 +0200
        Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-07-29 08:20 +0200
          Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Arend van Spriel <arend.vanspriel@broadcom.com> - 2016-07-30 14:50 +0200
            Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-07-30 19:00 +0200
              Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-07-31 09:30 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-08-01 14:40 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-02 00:40 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-08-02 08:00 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-02 08:40 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-08-02 09:00 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-02 10:00 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-08-03 09:10 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-08-03 18:20 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-03 20:20 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-03 18:50 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-03 20:50 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Bjorn Andersson <bjorn.andersson@linaro.org> - 2016-08-04 00:40 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-08-03 09:50 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Arend van Spriel <arend.vanspriel@broadcom.com> - 2016-08-03 13:50 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-03 17:20 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-08-03 17:40 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Arend van Spriel <arend.vanspriel@broadcom.com> - 2016-08-03 23:00 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-03 18:10 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Bjorn Andersson <bjorn.andersson@linaro.org> - 2016-08-03 19:50 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-03 22:40 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-01 22:20 +0200
              Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Bjorn Andersson <bjorn.andersson@linaro.org> - 2016-08-01 19:30 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-08-01 22:20 +0200
                Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of  completion Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-08-01 23:50 +0200
            Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-07-31 09:20 +0200
  [RFC v0 2/8] selftests: firmware: do not clutter output Daniel Wagner <wagi@monom.org> - 2016-07-28 10:00 +0200
  [RFC v0 6/8] remoteproc: use firmware_stat instead of completion Daniel Wagner <wagi@monom.org> - 2016-07-28 10:00 +0200
  [RFC v0 3/8] firmware: Factor out firmware load helpers Daniel Wagner <wagi@monom.org> - 2016-07-28 10:00 +0200
    Re: [RFC v0 3/8] firmware: Factor out firmware load helpers Dan Williams <dcbw@redhat.com> - 2016-07-28 17:10 +0200
      Re: [RFC v0 3/8] firmware: Factor out firmware load helpers Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-07-29 08:10 +0200
    Re: [RFC v0 3/8] firmware: Factor out firmware load helpers Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-07-28 20:00 +0200
      Re: [RFC v0 3/8] firmware: Factor out firmware load helpers Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-07-29 08:10 +0200
  [RFC v0 4/8] Input: goodix: use firmware_stat instead of completion Daniel Wagner <wagi@monom.org> - 2016-07-28 10:00 +0200
    Re: [RFC v0 4/8] Input: goodix: use firmware_stat instead of  completion Bastien Nocera <hadess@hadess.net> - 2016-07-28 13:30 +0200
      Re: [RFC v0 4/8] Input: goodix: use firmware_stat instead of  completion Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-07-28 14:10 +0200
        Re: [RFC v0 4/8] Input: goodix: use firmware_stat instead of  completion Bastien Nocera <hadess@hadess.net> - 2016-07-28 14:30 +0200
          Re: [RFC v0 4/8] Input: goodix: use firmware_stat instead of  completion Daniel Wagner <daniel.wagner@bmw-carit.de> - 2016-07-28 15:20 +0200
  [RFC v0 1/8] selftests: firmware: do not abort test too early Daniel Wagner <wagi@monom.org> - 2016-07-28 10:00 +0200

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