From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Wed, 31 Dec 2014 19:05:23 +0100 Subject: [U-Boot] Make "usb start" only start / scan usb once ? In-Reply-To: <5475CB27.7000704@redhat.com> References: <5475CB27.7000704@redhat.com> Message-ID: <201412311905.23503.marex@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Wednesday, November 26, 2014 at 01:44:23 PM, Hans de Goede wrote: > Hi, Hello Hans, > Currently we've this magic in include/config_distro_bootcmd.h to avoid > scanning the usb bus multiple times. > > And it does not work when also using an usb keyboard because then the > preboot command has already scanned the bus, so we're still scanning it > twice. > > While discussing my latest attempt at fixing this: > > http://patchwork.ozlabs.org/patch/413394/ > http://patchwork.ozlabs.org/patch/413395/ > > With Ian, Ian said why not simply make "usb start" keep track of if it > already has started things, and then we can remove all the magic for it > from include/config_distro_bootcmd.h and just call it unconditionally. > > This would also cause "usb start" and "usb reset" to actually do something > different, where as currently they are 100% the same. > > I must say I like this idea, the only downside is, that it could be seen > as a break of the u-boot cmdline API, one could easily argue it is not, > because usb will be started by "usb start" if necessary, and people can > still force a rescan with "usb reset". > > So any input on this, specifically would a patch-set to make "usb start" > start usb only once (per boot) be acceptable ? It just makes a lot of sense, so yes. You're right it'd break the command like API and it might be a surprise to some, but you're also right that the current "way of things" is confusing and possibly even wrong. Apologies I got back to you so late. Best regards, Marek Vasut