On Tue, Apr 14, 2015 at 11:56:26AM -0400, Andy Lutomirski wrote: > On Tue, Apr 14, 2015 at 10:08 AM, Greg Kroah-Hartman > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Apr 14, 2015 at 05:44:55PM +0800, Kweh, Hock Leong wrote: > >> From: "Kweh, Hock Leong" <hock.leong.kweh@xxxxxxxxx> > >> > >> Introduce this new API for loading firmware from a specific location > >> instead of /lib/firmware/ by providing a full path to the firmware > >> file. > > > > Ick, why would we want this? > > > > Because this mechanism should still work even if /lib is unwriteable > (e.g it's on squashfs or a read-only NFS root). Why would a filesystem need to be writable to read a firmware blob from? > In this regard, UEFI capsules are very much unlike firmware_class > firmware. firmware_class firmwise is kind of like device drivers; it > generally comes from the same vendor as your kernel image and > /lib/modules, and it can be updated by the same mechanism. UEFI > capsules, on the other hand, are one-time things that should be loaded > at the explicit request of the admin. Just like BIOS updates, which use the firmware interface. > There is no reason whatsoever > that they should exist on persistent storage, and, in fact, there's a > very good reason that they should not. On little embedded devices, > which will apparently be the initial users of this code, keeping the > capsules around is a waste of valuable space. > > This is why I think that the right approach would be to avoid using > firmware_class entirely for this. IMO a simple_char device would be > the way to go (hint hint...) but other simple approaches are certainly > possible. A char device would be present all the time, like a sysfs file to write the firmware to, so I don't see the difference here. For a char device, you would just do the normal open/write/close, just like for the firmware interface, what is the difference? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
