From: Michal J. <sp...@ge...> - 2005-03-10 00:16:54
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On Wed, Mar 09, 2005 at 04:40:09PM +0100, Arnd Bergmann wrote: > Ok, I now saw that you call call_usermodehelper with wait=3D=3D1. Why is = that > necessary? If you don't wait there, you don't need any hacks around the > console semaphore, because the helper will simply wait for change_console > to finish. That could work, assuming that: a) the helper can always finish unpacking the image before=20 change_console releases the semaphore b) the console is not redrawn at one point before change_console is=20 finished (I'm sorry, I don't have time to check that right now) If one of this assumptions is wrong, we would end up with first=20 displaying the wrong background picture and then quickly painting the new one (I doubt this would make a good impression on the user..). =20 > > What are the alternatives to the ioctl? A relatively clean way of > > feeding the data back to the kernel would be using sysfs. However, to > > make it sane we would have to export the various components of struct > > vc_splash in /sys/class/tty/tty<x> (otherwise, we would probabky have > > to pass aggreaget data types through a sysfs entry -- something that is > > IMO much worse than an ioctl). That however could be a little > > problematic -- tty_class is currently defined as a class_simple. > > To add entries other than the standard 'dev' we would have to define a > > completely new class, right? That sounds like a rather intrusive > > change.. >=20 > Right. I don't think that sysfs is the right interface for this problem. > For a short moment I had the idea that you could write an escape sequence > to the tty device, but that would race against the regular output. > An ioctl on the tty device is probably the best you can do here, but > if that's not possible, creating a misc device in order to do ioctl on it > is a rather ugly hack. Agreed, that might not be the nicest thing to do, but it just seems there isn't much of a choice in this situation. I'm going to be away for the next 10 days or so. When I get back I'll start testing some of the proposed changes. Maybe by using things like firmware_request it would at least be possible to make the splash interface a little simpler. Live long and prosper. --=20 Michal 'Spock' Januszewski Gentoo Linux Developer cell: +48504917690 http://dev.gentoo.org/~spock/ JID: sp...@im... freenode: #gentoo-dev, #gentoo-pl |