linux-kernel - Re: [PATCH 2/2] intel_microcode, Fix long microcode load time when firmware file is missing

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Message-ID: <CACVXFVP+RdNp_tkdfEBicE1S-92mwrS2w24pZ9pYu-5tR9ghTA@mail.gmail.com>
Date:	Tue, 22 Oct 2013 10:43:18 +0800
From:	Ming Lei <ming.lei@...onical.com>
To:	Prarit Bhargava <prarit@...hat.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	x86@...nel.org,
	Andreas Herrmann <herrmann.der.user@...glemail.com>,
	tigran@...azian.fsnet.co.uk
Subject: Re: [PATCH 2/2] intel_microcode, Fix long microcode load time when
 firmware file is missing

On Mon, Oct 21, 2013 at 10:25 PM, Prarit Bhargava <prarit@...hat.com> wrote:
>
>
> On 10/21/2013 08:32 AM, Ming Lei wrote:
>> On Mon, Oct 21, 2013 at 8:26 PM, Prarit Bhargava <prarit@...hat.com> wrote:
>>>>
>>>> And why don't you pass FW_ACTION_HOTPLUG? and you are sure
>>>> that udev isn't required to handle your microcode update request?
>>>>
>>>
>>> AFAICT in both cases, udev wasn't required to handle the cpu microcode update.
>>> Both drivers use CMH to load the firmware which removes the need for udev to do
>>> anything.  Admittedly maybe I've missed some odd use case but I don't think it
>>> is necessary.
>>
>> OK, so I guess the CMH still need uevent to get notified, right?
>
> The code as it is _currently_ written does not use uevents to load the processor
> firmware.  ie) call_usermodehelper does not need uevent to get notified, so I
> think FW_ACTION_NOHOTPLUG is correct.

You need to make sure your patch won't break userspace in old
distribution with your _currently_ code.

Actually if udev isn't used in your user space, the timeout issue
won't be triggered because it is blocked by udev.

Thanks,
--
Ming Lei
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