On Thu, Jun 25, 2009 at 6:13 PM, Greg KH<greg@xxxxxxxxx> wrote: > On Thu, Jun 25, 2009 at 05:57:51PM +0100, Will Newton wrote: >> On Thu, Jun 25, 2009 at 5:28 PM, Greg KH<greg@xxxxxxxxx> wrote: >> > On Thu, Jun 25, 2009 at 04:53:07PM +0100, Will Newton wrote: >> >> On Thu, Jun 25, 2009 at 4:18 PM, Greg KH<greg@xxxxxxxxx> wrote: >> >> > On Thu, Jun 25, 2009 at 11:36:29AM +0100, Will Newton wrote: >> >> >> Hi all, >> >> >> >> >> >> I'm trying to get the libertas driver working on an embedded >> >> >> development board and I've run into what looks like a sysfs problem. >> >> >> Although I'm actually using the BusyBox mdev hotplug helper rather >> >> >> than udev, I hope this is the right list to be asking this question. >> >> > >> >> > For busybox questions, not really, but we reserve the right to poke fun >> >> > at you for using mdev :) >> >> > >> >> >> What appears to be happening is I get my initramfs extracted, so I >> >> >> have access to the various necessary files including the hotplug >> >> >> helper and my firmware files. This step is taken care of by the rootfs >> >> >> initcall level. Then the driver initcalls are run, including the >> >> >> libertas setup routines, which call request_firmware. request_firmware >> >> >> fires off a uevent and calls the hotplug helper. The hotplug helper >> >> >> looks for the /sys/class/firmware entry for the libertas device, but >> >> >> it doesn't find one because I don't appear to have a mounted sysfs on >> >> >> the /sys mountpoint. >> >> >> >> >> >> So my question is: who should be mounting sysfs here? init will mount >> >> >> sysfs, but is run much later than the device initcalls. >> >> > >> >> > You need to mount sysfs as one of the first things to have happen. Look >> >> > at your distro's startup scripts as an example of this. >> >> >> >> Yes, I want my sysfs mounted as early as possible, but userspace (via >> >> /sbin/init) does not get a chance to do this until after the device >> >> initcalls have been run. I'm interested to know if there's a standard >> >> way to get sysfs mounted before /sbin/init is run. >> > >> > There isn't. >> >> Ok, so we cannot expect sysfs to be mounted on /sys before /sbin/init >> has been run? > > How would that possibly happen? > >> What do we do with callers of request_firmware prior to /sbin/init >> running? > > They would fail, as no userspace filesystems would be mounted yet to > provide the firmware in the firstplace. My initramfs has the firmware in it. I thought this was one of the reasons one might use an initramfs, to load drivers and firmware for your root device e.g. network devices for nfs root. >> Should drivers that require firmware always be modules? > > Depends on your system setup :) > > You could use an initramfs to solve this problem :) Well I do have an initramfs (in fact it's all I have), but I'm not sure how I can solve this problem with it. The initramfs is extracted just fine, but I'm not sure if it provides me with a way to mount sysfs before the device initcalls occur. >> I would rather build in my drivers monolithically if possible for ease >> of deployment and boot speed. >> >> Is there some non-standard other way of mounting sysfs people are >> using in this situation? > > Possibly an initramfs? > > Or just replay the uevents when init starts up, after you have mounted > sysfs, and other filesystems, so that the firmware can be properly > loaded. That is what almost all distros do. Can udev help with this? Have the distros got a standard way of doing this? It sounds slightly complex... Thanks for your patience, -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
