From: Bill Gatliff <bgat@billgatliff•com>
To: Paul Mundt <lethal@linux-sh•org>
Cc: linux-embedded <linux-embedded@vger•kernel.org>,
Linux/PPC Development <linuxppc-dev@ozlabs•org>
Subject: Re: A better way to sequence driver initialization?
Date: Sat, 10 Apr 2010 22:30:20 -0500 [thread overview]
Message-ID: <4BC1424C.8030309@billgatliff.com> (raw)
In-Reply-To: <20100411014751.GB16099@linux-sh.org>
Paul Mundt wrote:
> In some cases that might be valid, but there are many cases where drivers
> can reconfigure their capability sets based on which GPIOs are and aren't
> available. Just because a pin isn't available doesn't make it a
> show-stopper for the probe path..
>
Understood.
I just tweaked my kernel to run all probe()s in their own kthreads.
The results were a mixed bag, as expected.
On the one hand, it's pretty cool to see everything running in parallel!
On the other hand, I can see now yet another big reason why a probe
free-for-all won't work. Busses are also devices, so there are plenty
of places where a device for a particular bus type won't be able to
probe because the target bus simply doesn't exist yet. That's yet
another dependency that I hadn't thought about.
Were I to rewrite Linux :), I would make probing parallel from the
beginning. But I think I'm going to have to settle for now with
kthreading my probes that might want to sleep, and adding a wait queue
to gpio_request() and a few others. It ain't perfect, but it is
achieveable. *sigh*
b.g.
--
Bill Gatliff
bgat@billgatliff•com
next prev parent reply other threads:[~2010-04-11 3:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-09 19:23 A better way to sequence driver initialization? Bill Gatliff
2010-04-10 3:54 ` Bill Gatliff
2010-04-10 3:59 ` Bill Gatliff
2010-04-10 4:19 ` Bill Gatliff
2010-04-10 5:29 ` Grant Likely
2010-04-10 13:56 ` Bill Gatliff
2010-04-10 8:53 ` Benjamin Herrenschmidt
2010-04-10 13:35 ` Bill Gatliff
2010-04-10 23:39 ` Paul Mundt
2010-04-10 23:47 ` Grant Likely
2010-04-11 1:33 ` Bill Gatliff
2010-04-11 1:47 ` Paul Mundt
2010-04-11 3:30 ` Bill Gatliff [this message]
2010-04-11 1:31 ` Bill Gatliff
2010-04-11 7:26 ` Benjamin Herrenschmidt
2010-04-11 7:18 ` Benjamin Herrenschmidt
2010-04-11 7:15 ` Benjamin Herrenschmidt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4BC1424C.8030309@billgatliff.com \
--to=bgat@billgatliff$(echo .)com \
--cc=lethal@linux-sh$(echo .)org \
--cc=linux-embedded@vger$(echo .)kernel.org \
--cc=linuxppc-dev@ozlabs$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox