On Wed, 28 Jun 2017 12:36:35 +0200 Daniel Vetter <daniel.vetter@xxxxxxxx> wrote: > There's a bunch of folks who're trying to make printk less > contended and faster, but there's a problem: printk uses the > console_lock, and the console lock has become the BKL for all things > fbdev/fbcon, which in turn pulled in half the drm subsystem under that > lock. That's awkward. Yes - very. Although if you implement your console printing method with sufficient cunning it shouldn't cause much latency in most cases but for unaccelerated fb it's really bad. It also makes it unnecessarily hard for a drm driver to accelerate console output. > 4. Push console_lock down the call-chain, until it is down in > console_register again. I don't think that's actually going to work out. To fix it is going to need more invasive changes so that you can 'create' a console and set it up separately to actually 'enabling' it when you make it visible and start scribbling. I don't see any other way to make the changeover locking saner at this point without still having huge potential stalls in printk(). Reviewed-by: Alan Cox <alan@xxxxxxxxxxxxxxx> Alan _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
