Messages in this thread | | | Date | Thu, 09 May 2013 09:26:06 +0200 | From | Takashi Iwai <> | Subject | Re: [PATCH 0/3] firmware: Fix usermodehelper deadlock at shutdown |
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At Wed, 8 May 2013 20:46:43 +0200, Kay Sievers wrote: > > On Wed, May 8, 2013 at 6:26 PM, Takashi Iwai <tiwai@suse.de> wrote: > > At Thu, 9 May 2013 00:07:17 +0800, > > Ming Lei wrote: > > >> On Wed, May 8, 2013 at 2:56 PM, Takashi Iwai <tiwai@suse.de> wrote: > >> > Hi, > >> > > >> > this is a series of patches for the issue we faced in the firmware > >> > loader code during debugging the problem with dell_rbu driver with > >> > 3.9 kernel. > >> > > >> > The original problem was that the shutdown gets stuck when DELL BIOS > >> > update is performed. This turned out to be a problem in the firmware > >> > loader. Although the reason of dell_rbu driver breakage is still > >> > >> Sorry, from these patchset, I can't see why it is a problem in firmware. > >> > >> > unclear, we should fix the firmware loader side, at least, not to > >> > stall during shutdown. > >> > >> Firstly you need to describe what/why is the stall? In fact, firmware > >> loading can't stall forever and it will timeout, but the current 60sec > >> timeout might be too long. > > > > The timeout check is activated only when uevent flag is set, and > > dell_rbu driver doesn't set it explicitly (because it's not supposed > > to be handled via udev or whatever). > > These use the firmware loader not in the way the interface was intended: > drivers/misc/lattice-ecp3-config.c > drivers/firmware/dell_rbu.c > > They just use the mechanism without any of the usual userspace setup. > It's really a nasty hack to hijack the interface that way. > > The commit 6e3eaab02028c4087a92711b20abb9e72cc803a7 is a pretty broken > idea to start with. If something triggers uevents during runtime which > is not uncommon, these on-demand silently created firmware devices > would get really confused and race against the udev firmware loader > which cancels the events. > > As if the userspace firmware loading in general wasn't a bad enough > idea already. :)
Luckily there are only few users, so conversion of such known drivers should be easy. But the major question is whether we are allowed to drop the non-hotplug f/w loading right now after years. It means a clear user-space breakage, and we don't want it as much as possible.
Takashi
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