[PATCH] Fix for USB media not found at boot

[Chao Shin]

在 Sun, 04 Oct 2009 07:52:45 +0800，Scott Long <scottl at samsco.org> 写道:

Hi all

Is there any newer patch/workarounds available?

> On Oct 3, 2009, at 12:51 PM, Marcel Moolenaar wrote:
>
>>
>> On Oct 3, 2009, at 9:00 AM, Hans Petter Selasky wrote:
>>
>>> On Saturday 03 October 2009 17:05:35 Scott Long wrote:
>>>> On Oct 3, 2009, at 4:30 AM, Hans Petter Selasky wrote:
>>>>> On Saturday 03 October 2009 10:19:57 Scott Long wrote:
>>>>>> config_intrhook system will sleep after all
>>>>>
>>>>> Then why do you need the intr hook callback?
>>>>
>>>> The config_intrhook lets you know that interrupts are enabled, the
>>>> scheduler is running, and mountroot hasn't run yet.  It provides a
>>>> very convenient and standard way to do exactly what we want with USB
>>>> enumeration.
>>>
>>> Hi,
>>>
>>> The root HUB attach and explore code is already running from a separate
>>> thread, so won't that be superfluous? I mean, the HUB explore code for  
>>> any USB
>>> HUB will not run until the scheduler is running anyway.
>>>
>>> In my opinion delaying the system until the boot disk is present is  
>>> just not
>>> good. We should rather be event driven, so that every time a new disk  
>>> becomes
>>> present it checks it for mountroot.
>>>
>>> while (1) {
>>>      if (mountroot is successful)
>>>          break;
>>>      if (ctrl+c is pressed)
>>>          manual_mountroot();
>>>      printf("Waiting 1 second for root-disk to appear. Press CTRL+C to
>>> abort.\n");
>>> 	   sleep(1);
>>> }
>>
>> Yes.
>>
>> The mount root code should keep a list of potential root devices to try  
>> and
>> it should try a device as soon as it appears. The current approach to  
>> block
>> the root mount simply because we want everything to be discovered  
>> before we
>> try to mount the root is preventing fast boots -- such as when the root  
>> is
>> a memory disk and you don't need to wait for anything...
>>
>> Put differently: it's rather odd to hold off the root mount when the  
>> root
>> device is already present...
>>
>> An approach like this also allows one to indefinitely wait for the root
>> device, which is a good feature to have...
>>
>>
>
> When /etc/rc tries to mount everything in the fstab, it'll fail the boot  
> if some of the devices haven't arrived in time.  An argument can be made  
> for fixing that as well, but we're starting to get beyond on the scope  
> of fixing what is needed for 8.0-RELEASE.
>
> Scott
>
>
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