lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 20 Feb 2012 11:01:50 +0100 From: "Arend van Spriel" <arend@...adcom.com> To: "Larry Finger" <Larry.Finger@...inger.net> cc: LKML <linux-kernel@...r.kernel.org>, driverdevel <devel@...verdev.osuosl.org>, wireless <linux-wireless@...r.kernel.org>, "linux-hotplug@...r.kernel.org" <linux-hotplug@...r.kernel.org>, "Kay Sievers" <kay.sievers@...y.org> Subject: Re: will these methods work with firmware loading? On 02/19/2012 07:40 PM, Larry Finger wrote: > I sent a previous messages to most of these lists, but got no answer, thus a > second try. > > When a driver loads firmware synchronously in the module_init() path using > request_firmware(), then there is trouble with timeouts when booting. > > I know that changing the request_firmware() call to request_firmware_nowait() > solves the problem; however, that gives some trouble for driver b43legacy as it > loads 3 or 4 firmware files depending on the hardware version. When I launch the > 3 or 4 nowait requests, I get an error because the system is trying to start > several tasks with the same name. Yep, the nowait api just kicks off a kernel thread for the firmware request. > Would it be OK to load the first file with the nowait version, and issue a > request_firmware() for the others from the callback routine? I think that would > not cause any problems, but I would like to get confirmation from an expert. No expert, but that is what I did although the chaining of firmware requests does not feel great. Especially for handling error flows. Johannes Berg and Kay Sievers mentioned need to unbind/rebind the driver upon failed firmware load, but I don't like the idea of building a timer-controlled retry mechanism. > Similarly, if I were to create a work queue, init and schedule it from > module_init(), and then use synchronous loads to get the firmware from the work > queue callback, would that get around the boot problem? I know it works as I > have trial patches; however, my version of udev is not one affected. This method > is very easy to implement, but again I would like confirmation from an expert. What boot problem are you referring to? The blocking modprobe? For that problem I would say yes. Also here the problem of handling error flows exist. If the driver is kicked of during boot with a initramfs missing the firmware, should we retry until the real root is mounted? Gr. AvS -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists