On 8 Sep 2014, Oliver Neukum said: > On Fri, 2014-09-05 at 16:17 +0100, Nix wrote: >> On 5 Sep 2014, Oliver Neukum verbalised: >> >> > On Fri, 2014-09-05 at 00:40 +0100, Nix wrote: >> >> I'm working around this confusing morass by rebooting into each test >> >> kernel, unplugging and replugging the entropy key if it was fubared, >> >> then rebooting into the same kernel again and seeing if it was still >> >> fubared. But this is not terribly fast, particularly not on a headless >> >> compact-flash-based Geode box which doesn't even complete booting >> >> without the entropy source which this bug cuts off :) so it'll be >> >> sometime tomorrow before I can get this bisection done, I'm afraid. >> > >> > Ugh. My sympathies. I cannot suggest a better method, I am afraid. >> >> Well, that method doesn't work. I've found pairs of kernels (e.g. >> 59a3d4c3631e553357b7305dc09db1990aa6757c and >> b05d59dfceaea72565b1648af929b037b0f96d7f) where each kernel works on its >> own (rebooting from that kernel into the same kernel keeps a working >> key, so I would normally assume that each kernel is OK) but rebooting >> from the first into the second yields a broken one if it was working >> before (so one of them must, in fact, be broken, but I have no clue >> which one). >> >> So I can't figure out how to bisect this. >> >> Any suggestions as to what failure-test I might use, or what other >> methods I might use to figure out what's going wrong? Not knowing >> anything about USB doesn't help here. I don't know for sure that this is >> a cdc-acm problem -- bisecting just the cdc-acm driver was fruitless -- >> so it might be something more generally USBish. > > Do your kernels work if you start with a known good kernel e.g. > 3.15 and then reboot?
That case works -- aha, so I could orchestrate it by going 3.15 -> test -> test -> reset to 3.15 -> test -> test ... i.e. a triple reboot cycle. Should have thought of that. God, what a pain :) I'll give it a try tonight. -- NULL && (void) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
