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From: Ming Lei <ming.lei@canonical.com>
To: Prarit Bhargava <prarit@redhat.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	x86@kernel.org,
	Andreas Herrmann <herrmann.der.user@googlemail.com>,
	tigran@aivazian.fsnet.co.uk
Subject: Re: [PATCH 1/2] firmware, fix request_firmware_nowait() freeze with no uevent
Date: Wed, 23 Oct 2013 12:16:19 +0800	[thread overview]
Message-ID: <CACVXFVMmp3gOpfEtjQ-fO62=RY+7_ZJ11UW89GXDPNKE61+keg@mail.gmail.com> (raw)
In-Reply-To: <526706FC.2070105@redhat.com>

On Wed, Oct 23, 2013 at 7:15 AM, Prarit Bhargava <prarit@redhat.com> wrote:
> On 10/21/2013 10:35 PM, Ming Lei wrote:
>>
>> That is why NOHOTPLUG isn't encouraged to be taken, actually
>> I don't suggest you to do that too, :-)
> Okay ... I can certainly switch to HOTPLUG.

OK, that should be the right approach.

>
>>
>> You need to make sure your approach won't break micro-code
>> update application in current/previous distributions.
>
> I've tested the following distributions today on a Dell PE 1850:  Ubuntu, SuSe,
> Linux Mint, and of course Fedora.  I do not see any issues with either the
> microcode update or the dell_rbu driver.  Unfortunately I do not have access to

Actually I am wondering if your tests are enough because kernel
can't break user-space, which means lots of previous old version
distributions should surely be covered, :-)

If you keep HOTPLUG, only change to request_firmware_nowait(),
that should be OK since the loading protocol between userspace and
kernel won't change wrt. microcode updating.

> a system that uses the lattice-ecp3-config, however, from code inspection it
> looks like the driver looks at a specific place for the FW update and then
> applies it via the call function in request_firmware_nowait() so it looks like
> it is solid too.
>
> I think maybe this patchset should be split into two separate submits, one for
> the microcode and the second to figure out if the code really should wait
> indefinitely.  AFAICT neither use case in the kernel expects an indefinite wait.

If you switch to HOTPLUG, you needn't worry about waiting indefinitely,
need you?

Thanks,
--
Ming Lei

  reply	other threads:[~2013-10-23  4:16 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-20 21:35 [PATCH 0/2] Improve firmware loading times on AMD and Intel Prarit Bhargava
2013-10-20 21:35 ` [PATCH 1/2] firmware, fix request_firmware_nowait() freeze with no uevent Prarit Bhargava
2013-10-21 12:24   ` Ming Lei
2013-10-21 22:24     ` Prarit Bhargava
2013-10-22  2:35       ` Ming Lei
2013-10-22 23:15         ` Prarit Bhargava
2013-10-23  4:16           ` Ming Lei [this message]
2013-10-23 10:36             ` Prarit Bhargava
2013-10-23 12:02               ` Prarit Bhargava
2013-10-23 13:21                 ` Ming Lei
2013-10-23 14:08                   ` Prarit Bhargava
2013-10-24  1:54                     ` Ming Lei
2013-10-24 11:17                 ` Henrique de Moraes Holschuh
2013-10-24 12:05                   ` Prarit Bhargava
2013-10-20 21:35 ` [PATCH 2/2] intel_microcode, Fix long microcode load time when firmware file is missing Prarit Bhargava
2013-10-21 12:20   ` Ming Lei
2013-10-21 12:26     ` Prarit Bhargava
2013-10-21 12:32       ` Ming Lei
2013-10-21 14:25         ` Prarit Bhargava
2013-10-22  2:43           ` Ming Lei
2013-10-22 23:16             ` Prarit Bhargava
2013-10-20 22:58 ` [PATCH 0/2] Improve firmware loading times on AMD and Intel Andi Kleen

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