From: "Luis R. Rodriguez" <mcgrof@kernel.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>,
Jeff Mahoney <jeffm@suse.com>, Takashi Iwai <tiwai@suse.de>,
Andrew Morton <akpm@linux-foundation.org>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>,
Daniel Wagner <daniel.wagner@bmw-carit.de>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Arend van Spriel <arend.vanspriel@broadcom.com>,
Daniel Wagner <wagi@monom.org>,
Bastien Nocera <hadess@hadess.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Johannes Berg <johannes.berg@intel.com>,
Kalle Valo <kvalo@codeaurora.org>,
Ohad Ben-Cohen <ohad@wizery.com>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
David Howells <dhowells@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
David Woodhouse <dwmw2@infradead.org>,
Julia Lawall <julia.lawall@lip6.fr>,
linux-input@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion
Date: Wed, 3 Aug 2016 20:08:20 +0200 [thread overview]
Message-ID: <20160803180820.GR3296@wotan.suse.de> (raw)
In-Reply-To: <20160803173955.GD13516@tuxbot>
On Wed, Aug 03, 2016 at 10:39:55AM -0700, Bjorn Andersson wrote:
> On Tue 02 Aug 00:41 PDT 2016, Luis R. Rodriguez 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.
> >
>
> I think we're on the same page, but just to make sure; I do not want the
> usermode helper,
Yay.
> I only want a way to wait for the firmware files to
> become available.
Sure.
> > Other than these two drivers I'd like hear to valid requirements for it.
> >
> > The existential issue is a real issue but it does not look impossible to
> > resolve. It may be a solution to bloat up the kernel with 100+ MB size just to
> > stuff built-in firmware to avoid this issue, but it does not mean a solution
> > is not possible.
> >
> > Remind me -- why can remoteproc not stuff the firmware in initramfs ?
> >
>
> RAM usage:
> Storing the files in initramfs would consume 100MB RAM, we would then
> allocate 100MB RAM for buffers during firmware loading and then we have
> the reserved 100MB for the peripherals. The buffers could be easily be
> removed with a mechanism for providing a buffer to the load operation,
> but we would still double the RAM consumption.
>
> Boot time:
> Enlarging the kernel by 100MB will give noticeable addition to boot
> times.
Right I see.. Since we read the full kernel...
> Development issues:
> I have numerous concerns related to this, e.g. not being able to side
> load the firmware files without rebuilding the initramfs. But most of
> these are not technical issues, but rather a matter of convenience.
>
> One large issue would be how to figure out how large to make the boot
> partition in your Android phone, to cope with potential future growth in
> firmware size - which has already proven to be a mess.
>
> Legal matters:
> Some of these firmware files are not redistributable, making it
> impossible for end users to rebuild their kernel without loosing
> functionality. There are even cases where these files are not allowed to
> share partition with GPL binaries.
>
>
> Most of these are just a major inconveniences to the developer but some
> are show stoppers; especially the legal matters. So if we wave this off
> as something people can live without then every downstream will sit on
> their own solution to reimplement it.
Thanks I'll document these into the firmware_class.
> > Anyway, here's a simple suggestion: fs/exec.c gets a sentinel file monitor
> > support per enum kernel_read_file_id. For instance we'd have one for
> > READING_FIRMWARE, one for READING_KEXEC_IMAGE, perhaps READING_POLICY, and this
> > would in turn be used as the system configurable deterministic file for
> > which to wait for to be present before enabling each enum kernel_read_file_id
> > type read.
> >
> > Thoughts ?
>
> That does sound like a good generic solution for our problem and for the
> other types of files as well. Do you have any ideas (patches?) on how
> each sentinel would be triggered?
>
> The only concern I can think of right now is that the
> firmware_class.path might point to a separate partition; but based on
> how the signaling of the sentinels are implemented this might not be an
> issue.
There's another simpler suggestion I'm getting too, will post in the other
thread.
Luis
next prev parent reply other threads:[~2016-08-03 20:34 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-28 7:55 [RFC v0 0/8] Reuse firmware loader helpers Daniel Wagner
2016-07-28 7:55 ` [RFC v0 1/8] selftests: firmware: do not abort test too early Daniel Wagner
2016-07-28 7:55 ` [RFC v0 2/8] selftests: firmware: do not clutter output Daniel Wagner
2016-07-28 7:55 ` [RFC v0 3/8] firmware: Factor out firmware load helpers Daniel Wagner
2016-07-28 15:01 ` Dan Williams
2016-07-29 6:07 ` Daniel Wagner
2016-07-28 17:57 ` Dmitry Torokhov
2016-07-29 6:08 ` Daniel Wagner
2016-07-28 7:55 ` [RFC v0 4/8] Input: goodix: use firmware_stat instead of completion Daniel Wagner
2016-07-28 11:22 ` Bastien Nocera
2016-07-28 11:59 ` Daniel Wagner
2016-07-28 12:20 ` Bastien Nocera
2016-07-28 13:10 ` Daniel Wagner
2016-07-28 7:55 ` [RFC v0 5/8] ath9k_htc: " Daniel Wagner
2016-07-28 7:55 ` [RFC v0 6/8] remoteproc: " Daniel Wagner
2016-07-28 7:55 ` [RFC v0 7/8] Input: ims-pcu: " Daniel Wagner
2016-07-28 18:33 ` Dmitry Torokhov
2016-07-28 19:01 ` Bjorn Andersson
2016-07-29 6:13 ` Daniel Wagner
2016-07-30 12:42 ` Arend van Spriel
2016-07-30 16:58 ` Luis R. Rodriguez
2016-07-31 7:23 ` Dmitry Torokhov
2016-08-01 12:26 ` Daniel Wagner
2016-08-01 19:44 ` Luis R. Rodriguez
2016-08-02 5:49 ` Daniel Wagner
2016-08-02 6:34 ` Luis R. Rodriguez
2016-08-02 6:53 ` Daniel Wagner
2016-08-02 7:41 ` Luis R. Rodriguez
2016-08-03 6:57 ` Daniel Wagner
2016-08-03 15:55 ` Luis R. Rodriguez
2016-08-03 16:18 ` Dmitry Torokhov
2016-08-03 17:37 ` Luis R. Rodriguez
2016-08-03 18:40 ` Luis R. Rodriguez
2016-08-03 22:26 ` Bjorn Andersson
2016-08-03 7:42 ` Dmitry Torokhov
2016-08-03 11:43 ` Arend van Spriel
2016-08-03 15:18 ` Luis R. Rodriguez
2016-08-03 15:35 ` Dmitry Torokhov
2016-08-03 20:42 ` Arend van Spriel
2016-08-03 16:03 ` Luis R. Rodriguez
2016-08-03 17:39 ` Bjorn Andersson
2016-08-03 18:08 ` Luis R. Rodriguez [this message]
2016-08-01 19:36 ` Luis R. Rodriguez
2016-08-01 17:19 ` Bjorn Andersson
2016-08-01 19:56 ` Luis R. Rodriguez
2016-08-01 21:34 ` Dmitry Torokhov
2016-07-31 7:17 ` Dmitry Torokhov
2016-07-28 7:55 ` [RFC v0 8/8] iwl4965: " Daniel Wagner
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