[U-Boot] [PATCH 0/2] Fix repeated USB scans problems

Stephen Warren
2015-01-08T00:19:03Z

On 01/07/2015 04:35 PM, Marek Vasut wrote:
> On Tuesday, January 06, 2015 at 06:02:57 PM, Stephen Warren wrote:
>> On 01/06/2015 06:27 AM, Hans de Goede wrote:
>>> Hi Marek & Stephen,
>>>
>>> As discussed before we've a problem where our standard bootcmds sometimes
>>> scan usb more then once, causing a large boot delay.
>>>
>>> Marek, as discussed with you before, this patch-set tackles this
>>> differently then previous sets, by simply making "usb start" a oneshot
>>> command (atleast until "usb stop" is called).
>>>
>>> Stephen the second patch then modifies config_distro_bootcmd.h to simply
>>> call "usb start" unconditionally, since calling it repeatedly now can be
>>> done without side-effects.
>>>
>>> Assuming you both like these patches, that leaves the question of how to
>>> merge them, they can be merged individually each through your own trees,
>>> or one of you can pick up both of them, I'll leave that to you.
>>
>> Users will have to get used to running "usb reset" rather than "usb
>> start", but I guess that's fine.
>
> Hi!
>
> So why do we not have "usb reset" only, why can we not discard the "usb start"
> altogether?

The whole point is that we need separate commands for:

* usb start: If USB isn't started, start it and scan the bus, else do
nothing.

This is used by automatic scripts that want to ensure that USB is
available, but not force bus rescans over and over.

* usb reset: If USB isn't started, start it. Always rescan the bus.

This is used by the user to force a rescan of the USB bus, if they know
they've plugged in a new device.

>> Should we rename "usb reset" to "usb restart"?
>
> No, let's not mess with the UI any more than we already did.

Well, it might not be such a bad idea if the semantics are changing, to
give people a heads-up?