On Sat, 2013-08-03 at 13:54 +0200, Rafael J. Wysocki wrote: > On Friday, August 02, 2013 08:48:09 PM Felipe Contreras wrote: > > On Fri, Aug 2, 2013 at 5:21 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > > > On Friday, August 02, 2013 04:31:37 PM Felipe Contreras wrote: > > >> On Fri, Aug 2, 2013 at 4:21 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > > >> > On Friday, August 02, 2013 02:12:49 PM Felipe Contreras wrote: > > >> > > >> >> You forgot this patch: > > >> >> > > >> >> https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/commit/?h=linux-next&id=3706231332d57072e0e2c0e59975443f3f18e673 > > >> >> > > >> >> Or do you think it's fine to boot these machines into a black screen? > > >> > > > >> > Seriously, what's wrong with you?! > > >> > > > >> > I didn't forget about it, I just didn't include it into this particular > > >> > pull request. > > >> > > > >> > And I'm not even sure I will push it for 3.11, because I prefer to revert > > >> > efaa14c for 3.11 if that's necessary to make your broken box work as before. > > >> > > >> The issue happens in more than just "my broken box", and yes, > > >> reverting that patch would help (in more than just my box), in the > > >> sense that at least Linux won't boot into a black screen. > > >> > > >> But the backlight control still wouldn't work, as it hasn't worked > > >> since v3.7, possibly in many ASUS laptops, for that you need more than > > >> just reverting efaa14c. > > > > > > Yes, last time it worked in 3.6 and in particular it doesn't work in 3.10. > > > My current goal is bring things back to the 3.10 state first, possibly without > > > introducing any new problems, because we're kind of late in the cycle. > > > That's better done by reverting stuff known to have introduced problems in > > > the first place and not by doing things that may introduce more of them. > > > > > > And your blacklisting patch has potential to introduce problems. Your goal is > > > to bring backlight control to the 3.6 state on that particular machine, but > > > the blacklist is done at the *system* level and very well may affect more > > > things than just backlight. You may not see any problems resulting from it > > > and you may not care even if there are some, but other users of it may use > > > different user space, for example, and may see problems that you're not seeing. > > > > > > That's why I'd very much prefer to do the revert at this point. > > > > Yes, that's fine, either the revert, or the patch I mentioned, or > > something else, but something has to be done, and it was better to do > > it in v3.11-rc4 than in v3.11-rc5, because that change itself can > > cause further problems. > > A revert can be done in -rc5 just fine. If we don't have a working fix this > week, I'll do the revert. > > > >> > Well, perhaps I just won't push it at all so that you actually can go and > > >> > complain to Linus about that ... > > >> > > >> That is very responsible from you. Screw the users, right? > > > > > > No, that's not my goal, sorry for disappointing you. > > > > > > The problem is that I'm not really convinced about the validity of the > > > blacklisting approach to begin with. As I said, the blacklisting is done > > > on the system level and the goal is to work around backlight control problems. > > > That sounds like a sledgehammer approach to me, which I don't really like. > > > If the blacklisting was more targeted, done at the video driver level etc., > > > I wouldn't really have any concerns about it, but that's not the case. > > > > > > And since people evidently could live for over 6 months with the backlight > > > control problems, maybe they'll survive some more time still and allow us to > > > find a better approach? > > > > They probably can survive without Linux at all, that doesn't mean we > > are doing our job. > > > > Let's do a though experiment, let's say you are right, and they can > > survive the 6 months it would take you to find the "perfect" solution, > > say in v3.13. What's wrong with having a partial solution in v3.12? If > > the blacklisting doesn't work properly (there's absolutely no evidence > > for that), then you revert it on v3.12.1. > > > > What's wrong with that approach? > > If the blacklisting leads to problems, they may not be reported in the 3.12 > time frame, but much later. For example because people won't realize that > the problems are caused by the blacklisting until much much later. And then > we'll be in a spot where whatever we do will break things for someone. > > And we had situations like that in the past, which is the source of my concern. > You obviously don't have that experience, or you won't be so eager to inflict > the blacklisting on everyone. > > Anyway, as you know, but conveniently don't mention, I asked some experienced > people for opinions about that. If they agree with you, we will add the > blacklist. If they don't, we won't add it. > > Rafael > I am opposed to this patch. On ThinkPad X230 I had problems with it. Felipe, come over to dark side. 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